UltraPress® Purifier Cartridge
Maintain your water security across borders and in the field. The UltraPress® Replacement Cartridge is a lightweight, battle-tested upgrade to your travel and survival loadout—trusted by professionals who operate where failure isn't an option.
"A prudent person foresees danger ahead and takes precautions. The simpleton goes blindly on and suffers the consequences. - Proverbs 27:12"
Removes Viruses, Bacteria & Protozoa
Eliminates 99.99% of viruses, 99.9999% of bacteria, and 99.9% of protozoan cysts, including Rotavirus, Hepatitis A, Norovirus, E. coli, Giardia, Cryptosporidium, and more.
Filters Harmful Contaminants
Electroadsorption and activated carbon remove silt, microplastics, heavy metals, PFAS, pesticides, and volatile organic compounds (VOCs).
Optimized for Foreign Travel
Trusted for international deployment in locations where even hotel tap water can’t be trusted. Ideal for contractors, diplomatic security, and global field work.
Compact & Lightweight
Smaller than the GeoPress cartridge, this model is ideal for reduced kit footprints or covert carry in urban environments.
Drink Mix Compatible
Compatible with the UltraPress® One-Way Valve, allowing use with electrolytes and hydration mixes without compromising filter integrity.
Locate the cartridge lock tab at the bottom of the Inner Press.
Pull the tab and unscrew the used cartridge (lefty loosey).
Insert the new cartridge and rotate clockwise until you feel a solid click.
If using drink mixes, install the One-Way Valve before pressing.
The numbers, flat and honest.
| Active Technology | Electroadsorption + ultra-powdered activated carbon |
|---|---|
| Removes | 99.99% Viruses 99.9999% Bacteria 99.9% Protozoan cysts Contaminants: microplastics, silt, PFAS, VOCs, pesticides, heavy metals, chlorine, and taste/odor compounds |
| Flow Rate | 10 seconds per 16.9 oz (3 L/min) |
| Cartridge Lifespan | 300 cycles (40 gal / 150L) or 3 years after first use |
| Shelf Life (Unopened) | 10 years |
| Size | 2.9" H × 2.7" W (7.3 × 6.7 cm) |
| Weight | 2.8 oz (80 g) |
| Compatibility | Grayl UltraPress® and Ultralight bottles |
| Drink Mix Compatibility | Works with UltraPress® One-Way Valve (sold separately) |
| Materials | BPA-free ABS food-grade plastic and food-grade silicone |
| Chemical-Free Operation | Yes |
| Testing Standards | Meets or exceeds NSF/ANSI 42 & 53; EPA microbial purification standards |
| Origin | Designed in the USA; media made in USA; cartridge assembled in China |
WHY YOU’RE BUYING FROM STAY READY.
We aren’t the Amazon of survival. We’re a small, opinionated shop that carries gear we’d stake our own lives on — and we back every piece with real support.
Curated
Every brand we carry has been vetted in the field by our team. If it doesn’t pass our 30-day use test, we don’t stock it.
Authenticated
Factory-direct from authorized dealers. No grey-market, no refurb, no knockoffs. Your warranty is real.
Supported
Real humans on phone, text, and email — seven days a week. We carry this gear ourselves and we stand behind it.
American
HQ in California. Orders ship from our US warehouse. US-based customer care.
PRESS-TO-PURIFY WATER BOTTLES
From a Seattle napkin sketch to the fastest, easiest portable water purifier in the world.
GRAYL started as a napkin sketch in a Seattle bar — an obsession with making the perfect portable water purifier. The first Kickstarter raised over $250,000, and today GRAYL's GeoPress and UltraPress let you press-purify water from streams, hotel sinks, wells, and lakes in seconds. The mission is straightforward: empower adventure with clean, safe water anywhere. A minimum of 1% of every sale goes to environmental charities and non-profits.
- Founded in Seattle, Washington
- Originated from a napkin sketch in a hometown Seattle bar
- Kickstarter campaign raised over $250,000
- GeoPress and UltraPress — press-to-purify in seconds
- 1% of every sale donated to environmental nonprofits
Answers, straight up.
Product-specific questions on the left. Shopping with SRO on the right. Both open-ended — hit us if we missed one.
How long does shipping take?
Most orders process within 1–3 business days from our warehouse. From there: 5–7 business days economy, 2–3 business days expedited, or overnight if you need it fast. Free economy shipping on orders over $150 (contiguous US). Alaska, Hawaii, and Pro Eagle / freight items are quoted at checkout. You’ll get a tracking number and link the moment your order ships.
What’s your return policy?
30 days from the day your order arrives. Gear has to come back unused, with all original tags, stickers, and packaging intact. For standard items we’ll send a prepaid return label and deduct return shipping from your refund. Oversized or freight returns are on you, unless the item showed up damaged, defective, or wrong — in which case we cover it.
Refunds hit your original payment method within 10 business days of approval.
What can’t I return?
Final-sale items, gift cards, food and drink products, personal-care items, anything customized or engraved, briefs (hygiene), and hazardous materials. If you’re not sure whether something qualifies, email us before you order — we’ll tell you straight.
Do you ship outside the contiguous US?
Yes. Alaska, Hawaii, and US territories ship on freight-quoted rates calculated after checkout. International orders are available worldwide at variable rates; duties and import fees are the customer’s responsibility. EU customers get a 14-day cancellation window per EU consumer law, on top of our standard return policy.
My package arrived damaged — what now?
Email info@stayreadyoutdoors.com within 7 days of delivery with your order number and clear photos of the damage (product + packaging). We’ll replace, refund, or ship a return label on us — no back-and-forth. Damaged, defective, or wrong-item claims never cost you shipping.
Can I talk to a human before buying?
Yes. Email info@stayreadyoutdoors.com — we answer every message ourselves, usually within a few hours during business days. We carry this gear, we use this gear, and we’d rather talk you out of a kit that doesn’t fit your mission than sell you the wrong one.
Do you offer a military/first-responder discount?
Yes. Active-duty and veteran military, police, fire, EMS, and medical first responders get 15% off every order. Verify through GovX at checkout — one-time, secure, and reusable across thousands of brands. Discount applies automatically once you’re verified.