Hinged and Slip-on Stop Collars – Accord with API 10D Standard
Drixet Drill Stop Bit Collar Set – Kit Includes: 1/8", 3/16”, 1/4”, 5/16”, 3/8”, 7/16” and 1/2-Inch with Allen Wrench to Tighten The Stops Set-Screws (7-Piece) - - Amazon.com
TP Stop Collars – Micro Fence
7-Pc . Split Collar Set | Rockler Woodworking and Hardware