Conmetall Wing Nut M10, A2 Stainless Steel.
Self-drilling screws have a hardened drill point that cuts through steel or timber and taps its own thread in one operation, with no pilot hole. Light section for thin steel; heavy section for thicker steel. Winged versions clear timber before biting into steel below.
Drive with a socket or hex bit. Supplied in a barcoded Conmetall retail prepack.