The grip module is designed to use all factory equipment that comes with a SIG P320: Fire control unit, magazine catch (reversible), slide stop, take down pin. The module accepts factory SIG P320 magazines (9mm) 17rd, and 21rd. The module is compatible with both Safety Selector equipped P320 and without. In order to work with Selector-equipped models, a small cut must be made. An interior outline has been molded into the part to assist with making the cut. We recommend a small rotary tool, such as a Dremel with a 1/8” burr bit. If this modification is not something you would like to perform, we offer it as an additional service which you can select on the store page before adding to cart.