door closing damper: Packing and Delivery: packing details: 1.each one is packed in a polybag. 2.100pcs/carton ,size:32cm×31cm×21cm. 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. 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) 60 195 6 15 25N-400N 64 194 6 15 25N-400N 90 230 6 15 25N-400N 90 245 6 15 25N-400N 150 365 6 15 25N-400N Product Features: superior design .reasonable price.fast delivery.excellent painting surface.high quality. Installation diagram: caution: Don't open,high compressure.