W8BYA
Silver Member
Howdy group. I came across a very large number of these new nuts & bolts but am not familiar with the stamping on the head. I suspect they are metric as the bolt measures exactly 3 cm in length and a standard 5/16-18 coarse will almost thread on but does not. I read it as 3F on one side then 8.8 across from that. Looks like a heavy Chromate coating for corrosion resistance.