Complete lower parts kit bundled with a nickel plated locking block. Both are frame components - everything needed to finish the lower in one package, for less than buying them separately. What's included Lower parts kit - trigger with trigger bar, trigger housing, trigger spring, slide lock, slide stop lever (Gen 3-style, wire spring), magazine catch, connector and pin set Two magazine catches included Nickel plated locking block - corrosion resistant plating over steel, drop-in replacement for the factory block Fitment Lower parts kit: Glock 43, 43X and 48 Locking block: Glock 42 / 43 / 43X / 48 Slimline Installation Fitting the locking block requires removing the trigger pin and locking block pin. No permanent modification and no gunsmithing required for a standard build, though a qualified armorer is recommended if you have not done this before. No slide, barrel or sights included. GLOCK is a federally registered trademark of Glock, Inc. and is one of many trademarks owned by Glock, Inc. or Glock Ges.m.b.H. Neither 3CR Tactical nor this site are affiliated in any manner with, or otherwise endorsed by, Glock, Inc. or Glock Ges.m.b.H. The use of "Glock" on this page is merely to advertise the sale of Glock pistols, parts, or components. For genuine Glock, Inc. and Glock Ges.m.b.H products, visit https://us.glock.com . About the slide stop lever: This kit uses a Gen 3-style slide stop lever with a wire spring, rather than the coil-spring design found in factory G43/G43X pistols. It works exactly the same. The only difference is the install order: install the slide stop after the locking block is in place, not before.