This is a Hogue Revolver Grip known as the Rubber Grip, model 25000.
Hogue's Monogrip for S&W N Frame Round Butt Revolvers is molded from a durable synthetic rubber that is not spongy or tacky. It gives that soft recoil absorbing feel without affecting accuracy. The material will not come apart or deteriorate and is resistant to all solvents and oils used around firearms. It has proportioned finger grooves" unique cobblestone texture and ambidextrous palm swell and is excellent for competition and concealed carry use. Fits S&W N Frame Round Butt Revolvers 29" 610" 625" 627" 629" and Magna Classic.
Features:
Fits S&W N Frame Round Butt Revolvers 29 610 625 627 629 and Magna Classic
Oil and solvent resistant
For competition and concealed carry use