The Pyro gets its name from its bright pins. This compact sight has a rugged design and four pins attached to mini spools that extend out the back of the sight body. Each spool has 2 feet of .019-inch-diameter fiber. One of the places where otherwise good sights fall short is the vulnerability of their fibers as they loop around to form the pinhead. The fibers on the Pyro are protected over this important span. You can quickly add or remove pins.