Maple Leaf VSR Hop Up Unit 2.0 with TDC Design for VSR platformsFeatures: Enhanced accuracy and consistency compared to traditional hop up chambers TDC (Top Dead Center) design enables highly precise adjustment of hop up Made from high quality, durable ABS plastic material Compatible with VSR 10 style rifles and similar systems No modification required for barrel installation Precisely engineered to fit snugly in the inner barrel Specs Material: High quality aluminum Compatibility: VSR 10 based bolt action sniper