Features and Benefits: Size: 5/16". Includes 3 in a pack. Spring loaded pilot “pops” the slug from the cutter. Low cost sheet metal hole-making. Made in the USA. When you don’t have a lot of holes to make, Blair cutters provide fast, accurate holes in materials up to 3/16" thick. Blair cutters are annular cutting tools that cut around the edge of the hole and eject the center as a slug. Because they’re hollow there’s no dead zone as with twist drills. And unlike hole saws, that rip and tear through the material, they quickly give you a quality, virtually burr-free hole.