








MIRA Safety
NBC-77 SOF® 40mm NATO Gas Mask Filter (CBRN)

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NBC-77 SOF® 40mm NATO Gas Mask Filter
CBRN / TIC / Reactor-Rated Filter with 20-Year Shelf Life
The NBC-77 SOF® is a professional-grade 40mm NATO (Rd 40 × 1/7”) CBRN filter engineered to provide comprehensive respiratory protection against all known chemical warfare agents, toxic industrial chemicals, biological threats, radioactive particulates, and radioactive iodine compounds. Designed for long-term readiness and operational durability, it combines CBRN, TIC, and reactor-rated filtration into a single cartridge.
With a 20-year factory-sealed shelf life, the NBC-77 SOF® significantly reduces lifecycle replacement costs compared to standard 5–7 year filters, making it an ideal choice for preparedness, professional response, and long-term storage. Its rugged hard-shell housing protects the filtration media from impact and environmental damage while maintaining compatibility with all standard 40mm NATO-threaded respirators and PAPRs.
This filter is certified under EN 14387:2004 + A1:2008 and carries the A2B2E2K2HgSXP3 D R REACTOR classification, placing it among the most broadly protective consumer-accessible filters available.
Key Capabilities & Design Features
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20-Year Shelf Life (Factory Sealed)
Designed for long-term storage with minimal degradation, reducing replacement cycles and cost of ownership. -
NATO-Standard 40mm Thread (Rd 40 × 1/7”)
Compatible with the majority of modern military, law-enforcement, and civilian full-face respirators and PAPRs. -
Comprehensive CBRN + TIC + Reactor Protection
Filters chemical warfare agents, industrial gases, riot control agents, particulates, and radioactive iodine (including methyl iodide). -
Rugged Impact-Resistant Housing
Hard-plastic shell protects filtration media during transport, storage, and operational use. -
Used by Military and CBRN Professionals Worldwide
Proven design trusted by special operations, civil defense, and preparedness professionals. -
Multiple Color Options
Available in Black, Ranger Green, and Sandstone (color does not affect performance).
Filter Classification (EN 14387)
A2B2E2K2HgSXP3 D R REACTOR
This classification indicates protection against:
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Organic gases and vapors (A2)
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Inorganic gases and vapors (B2)
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Acid gases and vapors (E2)
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Ammonia and amines (K2)
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Mercury vapors (Hg)
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Chemical warfare agents (SX)
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High-efficiency particulates (P3)
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Radioactive iodine / reactor-grade filtration (REACTOR)
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Dust clogging tested (D)
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Reusable (R)
Complete Technical Data — NBC-77 SOF® Filter
Physical Characteristics & Breathing Resistance
| Parameter | Specification |
|---|---|
| Diameter | 110 mm |
| Height | 85 mm |
| Weight | 335 g ±5% |
| Storage Time | 20 years (factory sealed) |
Breathing Resistance (EN 14387 + A1)
| Flow Rate | Requirement | NBC-77 SOF |
|---|---|---|
| 30 L/min | < 140 Pa | 260 Pa |
| 95 L/min | < 600 Pa | 980 Pa |
Particle Filtration Efficiency
| Test Medium | EN Requirement | NBC-77 SOF Performance |
|---|---|---|
| Sodium Chloride (NaCl) | 99.95% | >99.999% |
| Paraffin Oil | 99.95% | >99.999% |
Breakthrough Time & Dynamic Adsorption Capacity
(Tested per EN 14387 at 70% RH, 30 L/min)
| Filter Class | Test Gas | Concentration (ppm) | EN Min (min) | NBC-77 SOF (min) | DAC (g) |
|---|---|---|---|---|---|
| A2 | Cyclohexane | 5000 | 35 | 39 | 20.475 |
| B2 | Chlorine | 5000 | 20 | 45 | 20.250 |
| B2 | Hydrogen Sulphide | 5000 | 40 | >80 | >17.400 |
| B2 | Hydrogen Cyanide | 5000 | 25 | 50 | 8.400 |
| E2 | Sulphur Dioxide | 5000 | 20 | 25 | 9.975 |
| K2 | Ammonia | 5000 | 40 | 50 | 5.250 |
| Hg | Mercury Vapor | 13 mg/m³ | 100 hrs | >170 hrs | >3.900 |
| SX | Cyanogen Chloride | 2500 | 20 | 25 | 4.710 |
| SX | Chloropicrin | 5000 | 20 | 44 | 44.286 |
| SX | Phosgene | 5000 | 20 | >77 | >47.058 |
| REACTOR | Methyliodide¹³¹ | — | 2 hrs | >2 hrs | — |
Full Application Range
When used with a compatible respirator or PAPR, the NBC-77 SOF® provides protection against:
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Chemical warfare agents (nerve, blister, choking, blood agents)
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Riot control agents (CS, CN, CR, OC)
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Radioactive particles and radioactive iodine compounds
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Toxic industrial chemicals (TICs) including acids, solvents, ammonia, chlorine, mercury vapors
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Biological aerosols (bacteria, viruses, toxins, fungi)
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Smoke, dust, and combustion byproducts
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Agricultural chemicals and pesticides
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Industrial solvents such as benzene, toluene, vinyl chloride
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Arsenic-based compounds (Clark I & II, Adamsite)
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Mustard agents (H, HD, HN variants, Lewisite, CX)
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G-series and V-series nerve agents
Storage & Handling Requirements
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Store unopened filters between -5 °C to +30 °C, RH <80%
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Sealed filters tolerate -30 °C to +50 °C, RH <95%
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Do not clean, regenerate, or expose filters to water or compressed air
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Dispose of used filters according to local hazardous-waste regulations
Important Notes
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⚠️ Filters are sold individually
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⚠️ Gas mask not included
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⚠️ Color may vary due to availability (Black, Ranger Green, Sandstone)
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⚠️ Use only in environments with ≥19.5% oxygen
Product information
Stay Ready Outdoors — Return & Refund Policy
Last Updated: February 27th, 2026
At Stay Ready Outdoors, we stand behind the quality of our products and want you to be completely satisfied with your purchase. If you need to return an item, please review our policy below.
Returns
We offer a 30-day return policy, meaning you have 30 days from the date you receive your item to request a return.
Return Eligibility
To qualify for a return, your item must be in like-new condition, meeting the following criteria:
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Unworn, unwashed, and with all original tags and stickers still attached
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Free of any scents like perfume, cologne, or smoke
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Free of any marks, stains, or pet hair
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In its original packaging, including all accessories
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Must include proof of purchase (receipt or order number)
How to Start a Return
To initiate a return, email us at info@stayreadyoutdoors.com with your order details. Once approved, you’ll receive return instructions and a prepaid shipping label.
For standard parcel items:
The cost of return shipping will be deducted from your final refund.
For oversized or freight items:
Return shipping is the customer’s responsibility (see Oversized and Freight Item Returns below).
Important: Items sent back without prior approval will not be accepted.
Return Address
Stay Ready Outdoors
ATTN: Returns
15236 Las Flores Ave
La Mirada, CA 90638
Oversized and Freight Item Returns
Due to the size, weight, and freight handling requirements of certain products, free or prepaid return shipping does not apply to oversized or heavy items.
This includes, but is not limited to:
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Rooftop tents
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Pro Eagle jacks
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Large recovery equipment
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Freight-shipped or oversized products
Important details:
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Customers are responsible for return shipping costs on these items unless the product arrives damaged, defective, or incorrect.
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Original outbound shipping charges (if any) are non-refundable.
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Freight returns must be properly packaged and may require coordination with Stay Ready Outdoors support.
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Items must be returned in new, unused condition with original packaging and all components.
Stay Ready Outdoors reserves the right to determine whether an item qualifies as oversized or freight-required based on weight, dimensions, or carrier requirements.
Damaged, Defective, or Incorrect Items
Please inspect your order upon arrival. If your item is damaged, defective, or incorrect, contact us at info@stayreadyoutdoors.com within 7 days so we can evaluate and resolve the issue promptly.
Non-Returnable Items & Exceptions
Some items are non-returnable, including:
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Briefs (due to hygiene reasons)
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Sale items (these sales are final)
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Gift cards
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Engraved or customized items
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Perishable goods (e.g., food)
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Personal care items (e.g., hygiene or beauty products)
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Hazardous materials (e.g., flammable liquids or gases)
Food or Drink Products — All Sales Final
Due to the nature of long-term food storage, all sales on food or drink products are final. We do not accept returns or exchanges on food or drink products for any reason including incorrect order, change of mind, or shipping delays.
Replacements will only be issued in the event of a verified manufacturing defect or shipping damage, which must be reported within 5 days of delivery with supporting photo documentation.
Products Fulfilled via Shopify Collective
Some items sold by Stay Ready Outdoors are fulfilled by third-party vendors through Shopify Collective. These items follow slightly different return procedures:
Return Window
Returns must be initiated within 30 days of the purchase date.
Who Handles the Return
Returns and exchanges for these products are handled directly by the originating business. However, you may contact Stay Ready Outdoors at info@stayreadyoutdoors.com for assistance facilitating a return or exchange.
Customer Responsibility for Shipping Costs
Shipping cost responsibility varies by vendor. Some vendors offer free returns or exchanges, while others may require customers to pay return shipping.
Size Exchanges
If a return is for a size exchange only, the replacement item will be shipped once the original is received and inspected, following the vendor’s policy.
Refunds
If a refund is approved after inspection, the originating business will notify Stay Ready Outdoors and the refund will be processed to the original payment method.
Price Changes
Prices for Shopify Collective products are subject to change without notice.
Vendor-Specific Note
The Buffalo Wool Company
Items fulfilled by The Buffalo Wool Company through Shopify Collective follow the same return procedures listed above. Customers are responsible for return shipping costs unless otherwise stated by the vendor.
All other eligibility requirements and non-returnable item restrictions in our standard policy still apply unless otherwise stated.
Exchanges
The fastest way to exchange an item is to initiate a return for the original item and, once accepted, place a new, separate order for the desired item.
European Union Customers — 14-Day Cooling-Off Period
If your order was shipped to the European Union, you have the right to cancel or return it within 14 days of delivery for any reason.
To be eligible, items must be unused, with original tags and packaging, and include proof of purchase.
Refunds
Once we receive and inspect your return, we will notify you of approval. If approved, your refund will be issued to the original payment method within 10 business days, less applicable return shipping costs.
Please note:
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Your bank or credit card company may require additional time to post the refund.
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If you have not received your refund within 15 business days of approval, contact info@stayreadyoutdoors.com.
Need Help?
If you have any questions about your return or refund, we’re here to help:
Email: info@stayreadyoutdoors.com

