Pre-Formed Lamination Kit #LK-10. 4" - formed for #1-1/2 and 1-3/4 square jaw Northwoods coil springs. These kits are used to widen and strengthen a trap's jaws to help prevent foot damage, and to keep hard fighting animals from dislodging the jaws from the frame. As the name says, these are 3/16" rod cut and formed to fit a specific sized trap. Just clamp and weld. Each kit contains 24 rods, enough to do one dozen traps.