PPS CNC Aluminum Upgrade Power Up Reinforced Piston For Spring Powered SVD Dragunov Rifles AirsoftPPS CNC Aluminum Upgrade Power Up Reinforced Piston For Spring Powered SVD Dragunov Rifles Airsoft Made out of CNC Aluminum High Pressure Piston. It consists of lightweight duralumin body steel and capture most metallic piston head with the bearing. Its low weight warrants smooth operation and precisely spaced tapered hole combined with two o rings optimally enhance performance. Bearing on the piston head prevents undesirable twisting of spring. The