for Glock Gen 4 Grip Plug Fits 20, 21, 40, 41 NDZ P7 Plain Plain JP7 Grip Plug for GLOCK 20 21 41 - GEN4 ONLY - USE without BACKSTRAP installed - ONLY. Plain black - no logo Fits flush, prevents snagging, debris from entering or reaching trigger assembly and firing pin Quick install using a tight friction fit Helps guide mag. into mag well.