The Drill Stop Bit Collar Set will quickly and easily help you drill holes to exact depths and are ideal for production work and repeated drilling by positively locking anywhere along the bit. SPECS: Assorted Sizes: 1/8 in., 3/16 in., 1/4 in., 5/16 in., 3/8 in., 7/16 in., 1/2 in. and an Wrench QUALITY: The Durable Alloy Steel Setscrew Type Collar will stay sturdy when tightened and is specially designed not to damage the bits. DESIGN: With the Setscrew tight the collar will remain securely in place exactly where you put them and will accurately control the depth of the hole you are drilling. USES: Bit Limit Rings are used as a Shaft Collar on machinery and can be used on twist drill bits or brad point drills or any type of bit to prevent excessive drill bit penetration and for any job that uses a bit and needs precision.