Reliability and simplicity have made GLOCK® semi-automatic pistols a favored sidearm for law enforcement, military, and civilian use all over the world. The GLOCK 21 Gen4 Semi-Auto Pistol is a full-size service pistol, shooting the .45 ACP pistol cartridge, a standard military round for over 100 years with proven knock down power. The Gen4 Semi-Auto Pistol utilizes a dual recoil spring assembly that substantially increases service life of the pistol, and helps take the snap out of recoil, reducing muzzle flip for faster follow up shots. A modular back strap allows shooters to instantly customize the grip to an individual shooter’s hand size, or to cold weather gloves. Rough grip texturing on the Gen4’s polymer frame provides a sure hold on the pistol when hands are wet or sweaty, and the enlarged magazine catch is reversible, accommodating left- or right-handed shooters. An integral accessory rail in front of the trigger guard allows for the attachment of a plethora of aftermarket tactical flashlights or laser sights. The dovetailed rear sight is drift adjustable and has a white outline around its notch; the fixed front blade has a white dot. Sight acquisition is quick in any light. The GLOCK 21 Gen4 Semi-Auto Pistol is an ultra-reliable handgun that is easy to learn how to operate and maintain, making it an ideal choice for self-defense, whether it be for field carry, home defense, or bear protection in the back country. The model 21 Gen4 comes with three standard 13-round magazines, or three 10-round magazines that comply with various city or state restrictions on magazine capacity.