Flange Bolts standard: DIN6921 ,IFI 111 Surface: black,zinc plated,yellow zinc plated.....etc. Size:1/4"-1 1/2", M4-M36 Class: 2/5/8,48./10.9 Materials:stainless steel, carbon steel, brass, etc. MOQ:20ton Delivery:30days after order is confirmed Payment:T/T or L/C at sight.