1/4 x 3/8 Cheese head screw for use on Rolls Royce Phantom II engine shield. Rolls Royce part number K 2004. Material: 12L14 Steel Finish: Manganese phosphate Thread: 1/4-26 BSF Head OD: .390 Head thickness: .202 Length under head: .375 OAL: .577 Slot width: .065