The best designed 4- coil system on the market. The double torsion springs are made from the highest quality music wire available. The spring pin is made from the high tensile steel and will not bend. Heavy spring lock included. Kit #1 fits #1-1/2 Nothwood Round & Square jaw, #1 1-3/4 Northwood Round & Square jaw, #1.75 Victor Pro 2x2, and #1.65 Bridger. 1 kit will do 1 trap