WARNING: Torsion springs, extension springs, and related door hardware can cause serious injury or death if not handled and installed properly. Professional installation is recommended. Do NOT attempt to install springs or hardware yourself unless you have the proper tools, reasonable mechanical aptitude and experience, and upper arm strength. Read and understand all instructions before you begin work. Extension and torsion springs, along with attached hardware, are under extreme tension at all times. All tension must be released from springs before any work is performed. Torsion springs are black coated, corrosion resistant, oil tempered and made in the U.S.A. Includes pair of springs(left and right), nylon bushing and winding bars Springs come with a 3 year limited warranty ASIN B00HWF7XGK Size 36 Inch Color Black Shape Round Usage Residential Material metal Thickness 0.24 Inches Item Weight 30 pounds Part Number TS17243 Manufacturer SS Cutting Diameter 1.75 Inches Item model number TS17243 Assembled Diameter 1.75 Inches Batteries Included No Batteries Required No Included Components Two springs, two sets of winding cones and stationary cones and a pair of winding bars Item Package Quantity 1 Is Discontinued By Manufacturer No