Kit #4 Metric consists of 100 general purpose light-duty coil springs manufactured to metric standards. There are 10 different designs with 10 springs of each supplied. Springs are designed to function in 2.5mm to 7mm inside diameters and vary from 50mm to 100mm in overall length. This is a highly desirable assortment of springs, especially for repairs in foreign manufactured arms.

BLITZPAK #4M consists of a total of 20 light-duty metric springs, 2 of each design as described in Kit #4M.