Thermostate housing, in Ali.
So they won't crack or break on the inner lip.
I know you can already get metal ones, but there about 300, and made in the states I think.
So wonder how much they would be from China.
See there's lots of options for around £700. I think it's worth spending some time talking to different vendors and deciding what solution works best for you. When I was looking I made a list of what features I wanted/ need, then look for a ecu that has them all.