Feinwerkbau Breech seal (sold individualy) Read description

These are all breech seal, all look alike, but each serves on a different model
Blue breech seal, #1750.359.1, Rubber (Semi-hard) listed for (1x): C60, C62, 600, 601, 602, 603, P70, P70RT/P70FT, P75, For mod. 500, 800 and the mod.700, you need 2.

White breech seal, #3.2.000.109, Plastic (Hard): Listed for.; 602, 603, P70, P70RT-P70FT 
This white seal help keep the breech tightly closed to the barrel.

Black breech seal, #3.4.000.136, Rubber (Softer), listed for: Mod.; C55P-55P.