PEARCE GF INSERT G4 20/21/41. Fits model M20 21 40 and 41. This product will only fit Generation 4 frames. Made of a high impact polymer this insert is designed to keep out dust and debris as well as finish off the overall look of the frame. Allows for use with or without of the factory interchangeable backstraps. Specifications for PEARCE PGFI21G4 GF INSERT G4 20/21/41: Manufacturer: Pearce Grip Color: Black Fabric/Material: High Impact Polymer Magazine Capacity: 0 Round Package Contents: PEARCE PGFI21G4 GF INSERT G4 20/21/41 The PEARCE PGFI21G4 GF INSERT G4 20/21/41 is a quality addition to the Pearce Grip lineup. For more great deals on Magazines by Pearce Grip please browse our Pearce Grip Magazines page. PEARCE PGFI21G4 GF INSERT G4 20/21/41