Spiral Spring / Coil Spring / Auto Reel Spring / Cable Rewinder SpringMaterial: 62Si2MnA, 65Mn, SK4, SK5.Stainless Steel 201, 301, 303, 304.Power Springs, Auto Reel Springs, Balancer Springs, Vacuum Cleaner Springs, Engineering Springs, Tap Measure Springs, Starter Springs, Constant Force Springs, Music Box Springs, etc. Size, thickness or other specifications can be designed according to your demand.