Metric Countersunk Sealed Plug

That's what it's built for. The plug runs a male M18 x 1.5 metric thread, so it'll seat into a matching female port without any adapter needed. At 17.1mm long and 24mm across the wrench flats, it gives you enough engagement to get a solid seal on an open port you need blanked off.

Crafted from steel, this plug is designed for sealing applications in industrial environments where durability is crucial. It's a reliable solution built to withstand demanding settings.