Glock Backstrap/Beavertail Set for Glock 20/21/40/41 Black Polymer

The Glock Backstrap/Beavertail Set (OEM part 30819) is Glock's factory Modular Back Strap (MBS) system for the full-size Gen 4 Glock 20, 21, 40, and 41 pistols. It lets the shooter swap the rear of the grip frame to dial in trigger reach and grip circumference to their hand without any permanent modification to the pistol.

Molded in tough black polymer, the kit ships with everything needed to adjust the fit: two standard interchangeable backstraps in different grip sizes, two extended beavertail backstraps that position the web of the hand higher on the grip for a higher bore-axis hold, a replacement trigger housing pin, and the small installation tool Glock includes for driving that pin out. Drop the pin, slide the existing backstrap off the rear frame rail, slide the new one on, and reinstall the pin.

This is the correct OEM backstrap and beavertail kit for every Gen 4 frame variant of the G20, G21, G40, and G41, making it the direct factory replacement for lost or worn parts and a clean fit-tuning upgrade for long-slide G40 and G41 owners. Glock part number 30819.