POC Joint VPD Air Knee Guard Epidote Green X-SmallPOC Joint VPD Air Knee Guard X Small X Small. The lightweight VPD Air offers minimal knee coverage and has been developed for cyclists who want enhanced flexibility ventilation and freedom of movement. Made using the lightweight and impact absorbing VPD compound Reinforced stretch fabric for freedom of movement and durability Crash retention strap offers a comfortable fit Anti slip Neoprene on the inside keeps guard in place Low profile design fits