Polymer80 G21/20 Gen3 Compatible 80% Pistol Frame Kit for Glock 21/20 Gen3 Polymer Polymer80's PF45 80 percent Pistol Frame offers compatibility with for Glock 20/21 Gen3 components, and is an industry first. Features such as the extended beaver tail, double undercut trigger guard, and a thumb ledge considerably enhance the ergonomics allowing for an effective grip and improved recoil mitigation. The frame is constructed of a high-strength reinforced polymer with a Picatinny/STANAG compliant accessory rail. The kit includes a blank serialization plate, stainless steel locking block rail system and rear rail module, hardened rail system pins, a finishing jig, drill bits, and a end mill.This model has a black finish and features an aggressive and adaptable grip texture. - Enhanced Ergonomics and Features - High-Strength Reinforced Polymer Construction - Aggressive and Adaptable Grip Texture - Picatinny/STANAG Compliant Accessory Rail - Blank Serialization Plate - Stainless Steel Locking Block Rail System (LBRS™) - Stainless Steel Rear Rail Module (RRM™) - Hardened Pins for LBRS ™ and RRM™ - Complete Finishing Jig, Drill bits and End Mill Included - Compatible with Gen 3 for Glock® G20SF/G21SF Slide Assemblies - Compatible with for Glock® G20SF/G21SF Magazines - Patent Pending