Features: 1. Made of CNC machining aluminum 2. Easy to install and durable 3. Equipped with 2 springs of different hardness (Wire diameter:0.4mm & 0.5mm) 4. It can be used without filling oil 5. Improve the seal, no more rubber ring, no more oil leakage 6. Suitable for 1/18 TRX4M RC track cars Specifications: Material: Aluminum alloy (barrel body), iron (spring), stainless steel (axis, ball head), nylon (ball head), stainless steel (piston), rubber (sealing ring) Color: Titanium/Black/Red Weight: 10g(2Pcs) Uncompressed dimensions (hole to hole): 52mm Compressed dimensions (hole to hole): 40mm