Staplers (also called staple guns) are devices for fashioning materials together by the use of a staple: a single piece, parallel-pronged, unidirectional, metal fastener whose two legs are adjoined at the shoulder of the prong (called the crown). These devices are used to adhere thin pieces of material such as wood, plastic, sheet metal, and masonry. Sharing a namesake with its office-dwelling relative, industrial and construction-grade staplers operate similarly: staples are loaded into the device in a strip containing dozens of staples; the stapler shears an individual staple from the strip, applies pressure to the crown of the staple, and drives the staple into the workpieces utilizing the piercing advantage of the staple's sharp prongs. Unlike household staplers, staples inserted by staple guns do not utilize an anvil to enclose the staples legs. Instead, industrial staples rely strictly on the friction and clasp created by the displacement of the material in which it was inserted.
The main advantage of a staple is its ease of application and removal, the surface area provided by the staple crown, the ability to splice thin objects along seams, and enclosing items (such as wire) within the staple.
Staplers can be spring-loaded, pneumatic, or electric in design, and are typically exclusive to one or two staple sizes. Hammer tackers are an alternative to staples. These devices operate like a hammer: staples are inserted into the tacker's headand the kinetic swinging of the tool drives the staple into a material.