The Glock 20 features Glock's Safe Action system which provides a consistent trigger pull from the first to the last round; three automatic independently operating mechanical safeties. All three safeties disengage sequentially as the trigger is pulled and automatically reengage when the trigger is released; slide stop lever and the magazine catch are easily operated with the shooting hand. The advanced surface treatment of the slide minimizes light and reduces wear and tear and is corrosion resistant, even when operating in saltwater conditions. It has the same advanced surface treatment as the slide. Its extractor serves as a loaded chamber indicator to comply with the laws of certain states and its position may visually and physically indicate whether there is a cartridge in the chamber of the pistol. The Gen4 model features a modular back strap system makes it possible to instantly customize its grip to accommodate any hand size. The reversible magazine catch makes it ideal for left and right-handed shooters.