ATHENA Cilinderkit Ø54mm Yamaha YZ125 FLY Racing’s HDM (High Density FLY Racing’s HDM (High Density Memory) protectors are made of a special blend viscoelastic foam with memory function allowing for repeat impacts that passes CE EN1621 1 rating to level 1 100% cotton a removable bronze cylinder head cover a set of anodized exhaust valves and an engine top gasket set