A stair climber is a piece of exercise equipment designed to simulate the motion of climbing stairs. It typically consists of two foot pedals that move up and down in a stair-like motion, along with handlebars for support and stability. Users stand on the pedals and push down with their feet to ascend, engaging muscles in the legs, buttocks, and core. Stair climbers provide a low-impact cardiovascular workout that helps improve endurance, burn calories, and tone leg muscles. They're commonly found in gyms and are popular for home use as well.