This is a Pachmayr Gripper known as the Grip, model 3266.
Pachmayr Gripper grips are made from a specially formulated rubber compound which optimizes control and recoil absorption. The finger groove style is popular for combat shooting and hunting. A covered backstrap and slight palm swell fills the hand but is not so large as to be uncomfortable. Gripper grips are fully checkered for appearance as well as for control.
Features:
Black finish
Gripper Grip
Classic styling
Deep checkered finish
Designed to help you point straight
Finger Grooves
For S&W K/L Frame round butt