This is a B5 Systems Grip known as the P-Grip, model PGR-1120.
The B5 Systems Type 23 P-Grip is the most natural grip for taking a squared-off stance. Your hand will naturally find its optimal position thanks to its steep angle" extended tang" and palm-filling design. By ensuring proper trigger finger placement" this grip has been shown to improve shooting speed while correcting for any tendency to drift into a "chicken-wing" arm placement. The grip's no-slip texture was carefully engineered for hand comfort.
Features:
The most natural grip for taking a squared-off stance
Constructed of durable composite
Drop-in upgrade