Blue anodized plugs as used on the Hewland LG 500/600 on the oil filter as a plug, as used on the top of the transmission case as either a filler or an oiler by drilling and tapping for a pipe,  Comes with an aluminum washer for sealing. It is the uncommon BSPP 3/4" pipe thread. Best shipping would be with smallUSPS flat rate box- couldn't put it on the recommende shipping by E bay