I'm not a gun guy therefore google to the rescue and for others I'll paste it.
Pachmayr rubber handgun grips, introduced to the market in the early 1960’s, revolutionized the handgun market. Innovative, patented designs and materials have been the foundation of the grip line. One of Frank Pachmayr’s proudest accomplishments was the fact that scores of police officers around the country chose to privately purchase Pachmayr grips for their guns in a time when police departments did not provide guns for their personnel. In 1996, Lyman Products acquired Pachmayr and we have worked to continue his legacy in our line of Revolver Grips with classics like our American Legend Grips and innovative products such as the Diamond Pro Grip and our G10 and Renegade Grip line, as well as truly revolutionary concepts like our new GuardianGrips. Generations of shooters have benefitted from the experience designed into every Pachmayr grip.