Introducing the 7-Piece Drill Bit Stop Collar Set by POWERTEC. This impressive collection of bit stop collars create the perfect drill holes with high precision and uniform depth for your portable drilling and woodworking applications. They feature a split ring design used to control the depth of the hole you are drilling - eliminating over and under drilling. This also helps to provide a secure, dependable grip around the diameter of your drill bit - delivering quick and easy utility. PREMIUM DESIGN: Each collar is made with heavy-duty stainless steel for long-term durability. They will not mar your expensive drill bits as they never touch the bits. Unlike other brands, we have wisely marked each stop for easy bit identification and enhanced workflow. 7-pieces SET CONTAINS: 1/8 in. bit stop collar, 3/16 in. bit stop collar, 1/4 in. bit stop collar, 5/16 in. bit stop collar, 3/8 in. bit stop collar, 7/16 in. bit stop collar, 1/2 in. bit stop collar. INCLUDED BONUS: An Allen Wrench is supplied to help adjust and install/uninstall the stop bits and can also be used for other projects.