The Gregory Bite Valve Cover in Optic Blue is designed to keep your hydration systems bite valve clean and protected from dirt and dust during your adventures. Compatible with Gregorys DryLock Magnetic Bite Valve and all 3D Hydro Reservoirs, this cover features an integrated tether for secure attachment. To install, simply thread the tether over the hose before attaching the bite valve. The cover fits hoses with an outer diameter of up to 0.5 inches (13 mm). Constructed from durable HDPE and EVA materials, it measures 3 cm in height, width, and depth.