Air Valve （Fits FlexFlow & FlexFlow Pro）

Absolutely! The OASSAY filter is designed for much more than just the backcountry.

In addition to our 0.1-micron hollow-fiber membrane (which effectively blocks pathogens like bacteria and parasites), our filter features a NanoFlex Carbon layer. This advanced carbon layer significantly improves the taste of water and reduces heavy metals, water hardness, PFAS, and other chemical contaminants. It is the perfect companion for international travel, hotel tap water, and everyday use.

In most backcountry environments (like mountain streams, rivers, and lakes), the most common and significant threats arebacteria, parasites (protozoa), and organic pollutants.The OASSAY filter is specifically engineered to highly effectively remove these contaminants, ensuring your water is safe and great-tasting wherever your adventures take you.

In standardized laboratory tests conducted by SGS, the OASSAY filter achieved a >99.999% removal rate for the MS2 bacteriophage (the globally recognized surrogate used by the EPA and NSF for virus testing).

However, our research team recognizes that a virus’s behavior and physical state in nature can vary significantly depending on environmental conditions (like water chemistry and temperature). Out of an abundance of caution, we will not officially claim comprehensive virus filtration until we have completed the most rigorous, multi-condition certification testing available.

For your safety: If you are traveling to an area with a known high risk of viral contamination, we recommend using our filter in combination with chemical water purifiers (such as Aquatabs) for maximum protection. We anticipate sharing the results of our ongoing advanced testing by late 2026 or early 2027.

No. Please do not use the filter with seawater. OASSAY filters cannot remove dissolved salts, and filtering saltwater will damage the membrane.

For your safety, you should also avoid water sources that are clearly contaminated with industrial chemicals, heavy agricultural runoff (pesticides), or extremely thick mud and sediment.

You should backwash the filter whenever you notice a significant decrease in flow rate (especially after filtering cloudy or murky water), and always right before storing the filter long-term.

Do you need a special tool? Yes, backwashing requires a specific backwash pouch.

The great news is that starting in June 2026, OASSAY includes this backwash pouch in the box with every filter as a standard accessory. You do not need to purchase it separately.

Yes, the bottles in the FlexFlow Pro series are dishwasher safe.

⚠️ Important: The filter cartridge itself is NOT dishwasher safe. Please remember to remove the filter cartridge before placing the bottle or cap in the dishwasher.