The Carbided Modular System for the Sig Sauer P365 Macro allows you to interchange between your favorite backstraps at will by having the main portion of the grip module carbided separately to the backstraps. Third party companies like FDEZ WERX and Radian offer great options outside of the stock backstraps that can either be carbided or not with your grip module. The seam between the backstrap and the main grip module is subtle and does not affect the comfort and overall circumferential traction on the grip.