Sale Quick view Compare Bike Prizm MTB Adult Knee Guard (Black) FLY Bike Prizm MTB Adult Knee Guard (Black) RPF = Reaktiv Prizm Foam. FLY Racing has developed their own CE Approved protection. It is a high density memory foam that has been sliced with a prismatic pattern to allow the pad to mold to the shape of the... MSRP: £99.98 £49.99 Choose Options Add to Wish Lists