A Smith machine is a guided barbell system with fixed rails that keep the bar on a vertical or slightly angled path. It allows beginners and advanced lifters to perform squats, bench presses, overhead presses, and lunges with less balance demand. The fixed track makes it safer to train close to failure without a spotter. Many models include safety catches, adjustable hooks, and plate storage. It is widely used in commercial gyms and home gyms because it combines safety, versatility, and heavy-load potential.