Andibro 6 Pcs 1/4"-20 Inch(M6) Threaded Knob, 6 Star Shape Screw-On Type Thru Knob Nuts Hand Tighten Clamping Knobs Black Female Thread for a Holding Jig

Packing list: 6pcsThru Knob Nuts 6 Star Shape

Female thread type: 1/4"-20
Head diameter: 1.18 inch/30mm
Opening diameter: 0.24in/6mm 
Total height: 0.39 inch/10mm
Color:Black      
Material:   Plastic+Copper