This Sig Sauer P320 Compact Medium Grip Module is a genuine factory replacement part finished in a standard black polymer. It is designed to house P320 or P250 Fire Control Units in 9mm, .40 S & W, or .357 SIG that do not require a manual safety cutout. The "Medium" circumference provides a balanced, ergonomic feel suitable for a wide range of hand sizes and is intended for use with compact or carry-length slides. This assembly comes ready for immediate installation and includes a pre-installed, reversible magazine catch.