Vertex 4 Piece 15.5mm (.610")" T-Slot Clamping Nut Kit Specially made downward force for holding thin or small workpieces. Used for milling, drilling and EDM with a T-slot table. Kit includes 4 pieces each with a t-slot, clamping piece and bolts. Quick and easy setting with hex key wrench. Made of hardened tool steel. Supplied in a fitted wooden case. Made in Taiwan. Vertex # CK-3716.