There’s not much to say about sex bolts. You’ve got a female tube part and a male bolt part. The two go together and do wonderful things.
These are M4 machine screws with a matching M4 female rivnut. We recommend you predrill the hole with a 1mm or 2mm drill bit to prevent blow-out, then drill through again with a 5.5mm drill bit, before widening the top third of the hole with a 6mm drill bit to get the female half into the deck. If you drill the whole hole with a 6mm bit, you’re likely to find the sex bolt just spins in the deck instead of tightening up properly. If that happens, try sticking a piece of grip tape on one side of the female section when you put it into the deck, put pressure on the top of it, and hope it holds!