OSE 4-piece hatch screw-down kit Aluminum silver or blue anodized thumb screw and nut. The nut has holes drilled into it, to allow the glue to flow into them to supply a better bond to your hull. Each kit contains:(4) 530b25 4mm threaded nuts. (4) 530b12 4mm thumb screws. Measurements: See picture 2Colors available:Black, Blue, Red, or Silver