Garage door parts 1)Zinc plated steel 2)Overhead Length :15" 3)Push down bumper spring-4" 4)Approximate compression:10b/in 5)6"Travel 6)2"diameter rubber bumper 7)12gauage bracket for 3/8"bolts 8)ISO9001:2008 CE Packing: 1)Standard packing 2)Size of carton:44*36*16 3)10pairs/ctn 2.205kg/Pairs The pushes down spring bumpers are provided with rubber stop.The spring bumpers are available loose,without fixing material,or with 2different types of mounting plates including fixing material.