car parts: Parameters: 1.there are five parameters:extented length, sroke length, rod diameter, body diameter, force. 2.the parameters can be decided by buyers. Stroke length(mm) Extented length(studs) (mm) Rod diameter (mm) Body diameter (mm) Force range (N) 25-250 2×str+30mm 6 15 25N-400N 25-250 2×str+45mm 8 18 100N-800N 25-420 2×str+45mm 10 22 100N-1200N 25-420 2×str+45mm 12 22 100N-1600N 25-300 2×str+45mm 12 26 100N-1500N Packing and Delivery: packing details: 1. 1 pc/a plastic bag 2. the product number and the QTY printed on the carton 3. as your request. delivery details: it's up to your quantity. Certification: GB/T19001-2000-ISO9001:2000 standard. Item Gurantee Life: Through more than 50,000 times recitprocating fatigue test. warranty:one year. Product Features: long lifespan,superior design ,reasonable price,fast delivery,excellent paint surface,high quality. caution: Don't open,high compressure.