Helps secure, clamp down and optimize numerous t-track, fences, routing jig and fixture assemblies - accepts any application that utilizes a 5/16 inch -18 internal thread (also accepts most inch wide by 3/8 inch deep T-tracks); not work with inch t-track 5/16 inch -18 t-bolts: 1 inch , 1-1/2 inch , 2-1/2 inch and 3-1/2 inch length for project versatility; Bolt plates measure 17/32 inch wide x 13/16 inch long x 7/64 inch high. Hold Down Clamp Set is ideal for work holding, positioning, and fixturing for many woodworking or metalworking applications, including routers, drill presses, CNC, table saws, jigs, panels, vertical mills and more Our t-bolts, both 1/4 inch -20 and 5/16 inch - 18 have a head size of 17/32 inch wide x 13/16 inch long and 7/64 inch thick (Please see drawing). They are designed to fit Universal T-track or larger and not fit 1/4 inch or Mini T-track. Please check the size to verify that they work for your application. Colour:As Shown Material:Metal Package Contents: 1 * T-Track Hold Down Clamp Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.