Cnoc's Bite Valve Cap swaps a screw lid for one-handed, spill-free drinking straight from the flask. The soft silicone bite valve opens with a squeeze so you can sip on the move without stopping to unscrew anything, and the clear bite tube makes it easy to spot at a glance when it needs a clean. It threads onto any 28mm fitting, so it works as a straightforward upgrade or spare across Cnoc's 28mm range of collapsible flasks and bottles. Built from polypropylene and silicone, it's BPA and PVC free, and at just 10.1g it adds next to nothing to overall pack weight. Features: Soft silicone bite valve gives an efficient, spill-free drinking experience with just a squeeze. 28mm thread is compatible with all of Cnoc's 28mm products, for easy swapping between flasks and bottles. Clear bite tube makes it easy to see at a glance when the valve needs cleaning. BPA and PVC free construction. Lightweight at just 10.1g, adding negligible weight to a pack. Weight 10.1g Material Polypropylene & Silicone Thread Size 28mm Colour Blue