INCLUDES: (4) 5-Star Knobs, (4) T-Knobs and (8) 5/16”-18 T-Bolts (1", 1-1/2", 2-1/2" & 3-1/2 in length) FUNCTION: Helps secure, clamp down and optimize numerous t-track, fences, routing jig and fixture assemblies – accepts any application that utilizes a 5/16”-18 internal thread (also accepts most ¾ inch wide by 3/8 inch deep T-tracks); Will not work with ¼” t-track FEATURES: Premium black knobs constructed out of a robust and heat resistant Polypropylene plastic, paired with an ergonomic design for smooth handling and comfort, plus molded plated steel inserts that are corrosion and rust resistant and designed for anti-stripping EASY TO USE: Simply insert the head of the bolt into the track and align it with the threaded knob; These woodworking jig knobs can easily be utilized to enhance an assortment of applications, including your lathe, featherboards, saw, drill press and so much more SPECS: 5/16”-18 t-bolts: 1", 1-1/2", 2-1/2" and 3-1/2 in length for project versatility; Bolt plates measure 17/32” wide x 13/16” long x 7/64” high.