gas spring: Parameters: extended length:218mm stroke length:95mm cylinder diameter:8mm piston rod diameter:4mm force :50N Packing and Delivery: packing details: 1.each one be packed in a polybag. 2. 200pieces in a carton. 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: superior design ,reasonable price,fast delivery,excellent painting surface,high quality.caution: Don't open,high compressure.