This is an Iver Johnson Carbine extractor spring plunger. It fits the following models: - IVER JOHNSON | CARBINE | Extractor Spring Plunger - U.S. MILITARY | M1 CARBINE, M1A1, M2 CARBINE | Extractor Spring Plunger - UNIVERSAL | CARBINE | Extractor Spring Plunger - U.S. MILITARY | M1 CARBINE, M1A1 | Bolt, Complete, Flat - U.S. MILITARY | M2 CARBINE | Bolt, Round, Complete, NI - IVER JOHNSON | CARBINE | SUPER Bolt Assembly - U.S. MILITARY | M1 CARBINE, M1A1 | Bolt Assembly, Flat, Milled, Replacement