E. Emerson Tool Co. XCSB All-In-One Contractor Stop Block Use the stop block to terminate cuts or as a positioning stop when using your clamp as a fence for your drill press The E. Emerson Contractor Stop Block has a L-bolt that slides into either track on their straight edge clamps The large wing nut on top locks the block into position and additional micro adjustments can be made with the multi position bolt and lock nut Easy stop set up Micro-adjustment capability with a lock nut to handle tricky jobs Table extension capability for big jobs Stop Block fits into recessed tracks on the Contractor Straight Edge Clamping Tool Guide but will not work with A, Twin or Ultra series clamps Wing nut tightens to lock Stop Block into position