For many users, the Glock 21 Gen 4 is a typical and ultimate high-capacity .45 caliber combat pistol. It is, beyond doubt, trustworthy, precise, highly durable, and practically indestructible. The Glock 21 Gen 4 is even more durable than other Glock models. The Gen 4 models are also slightly slimmer and easier to grasp than the Gen 3. The Glock 21 model was issued only for its size, and Gen 4 improvements made it accessible to more shooters. The Gen 4 introduces a modular back strap system that makes the gun highly customizable and adjustable to any hand size. Earlier versions of the grip were a bit rough, and a new generation brings a finer textured finish on it, making it feels less abrasive while remaining solid. The finger grooves are also redesigned. A dual-recoil spring assembly is also added, making the shooters feel less of the recoil, as well as adding significant durability to the springs. The sights are basic, a simple white dot in front, and the white-outlined U-notch in the back. The finish on the slide is also less shiny and slippery. Another noticeable improvement is a magazine catch that has been improved to enable faster magazine swaps. All of the G21 pistols are proven as very accurate and this one is not an exception. Every change that has been made only enhances the abilities of this gun.