Finest quality coil springs, controlled-tension wound for smooth operation without binding under compression. “In-Hole” springs are made to fit inside restricted areas. “IN-HOLE” KITS - 12 Coil Springs; 6 sizes made to function freely inside holes from 3⁄32' (2.4mm) to 1⁄4' (4.7mm). 12' long (30.5cm). Kit # 1, ID-12; Light duty. Kit #2, ID-12; Heavy duty. SPECS: High tensile spring wire. 12' (30.5cm) long.