Ultraflask+ Filter Cap Size:42mm 360-degree sun protection

360-degree sun protection

and odor resistance of Merino with the comfort of an interlock knit

An excellent choice for lightweight backpacking

The Tempest 20 is the perfect panel-loading

Materials Performance mesh upper with overlays for added durability

Ultraflask+ Filter Cap Size:42mm 360-degree sun protectionRun 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.*Effectively removes common waterborne bacteria, such as E. coli (99. 999%) and parasitic cysts (99. 9999%) per HSF 42.