Run fast, filter faster. The UltraFlask+ Filter Cap threads seamless onto all of HydraPak&&';;s 42mm running flasks and handhelds for a lightweight, straightforward filtration solution. Featuring a traditional bite valve and cap design, runners can drink freshly filtered water directly through the high-flow Blaster valve. FILTER FACT SHEET | FILTER USER MANUAL *Effectively removes common waterborne bacteria, such as E.coli (99.999%) and parasitic cysts (99.9999%) per HSF 42. Weight 36 g / 1.3 oz Dimensions 42mm Material ABS, POM, Silicone, Hollow Fiber Care Avoid freezing filter. Freezing may ruin the hollow fiber membrane. If in freezing conditions we recommend you keep the filter in your pocket or near your body to prevent freezing.