Grip Force LLC makes an accessory that attaches to the backstrap of a Glock frame. It provides for a small beavertail extension and a change in the factory Glock grip angle. The design gives operators a higher grip than factory, ensuring more accurate shooting and better muzzle control under rapid fire shooting.
They are very reasonably priced at $27.
Ken Hackathorn likes it:
Dave Harrington’s test and evaluation: