These new rubber grips are molded with ergonomic, proportioned finger grooves - real finger grooves, not just small nonfunctional bumps. They are molded from our famous synthetic rubber that is not spongy or tacky, but gives that soft recoil absorbing feel, without effecting accuracy.To retain their shape they utilize light-weight synthetic inserts that chemically bonds to the rubber. This prevents them from delaminating or coming apart as can happen on brands with metal inserts.