We've never been able to buy them, so that is a welcome addition to the stock, thanks Mark at Surf Sail

The weight looks good too, most of the placcy ones were too heavy and 75g isn't too bad
Only thing is that flange is 3mm thick. Thus when routed you will have no hi density foam left at the perimeter, you will be setting the entire box into styro. Will need a divinycell block large enough to ensure the flange sits on top of hi density foam to prevent it rolling.
Still $20 vs $80 and not too heavy I reckon its a winner