Stainless steel A2 screws, any head form, DIN 912 or others. Flat head with flange, knurled M 4 x 8 or M 4 x 10 100.000/150.000 pcs. Alternative: Combi-Screw with well fixed spring washer (or toothed wahser) in stainless steel A2 M4 x 8 or M 4 x 10 100.000/150.000 pcs.