I use an HP Lip Relief loose ring snaffle which has the same covers...
I have not used a bit like that but is this of interest if you do dressage?
I think they are not legal.
https://www.britishdressage.co.uk/uploads/File/BD Approved Tack Equipment and Clothing wef 1 Jun 2018 v1.pdf
They are dressage legal. There is even a tick next to one on that link
I’m not sure but this is what I’m looking at. Sleeved cheeks okay but shaped sleeved cheeks not:
View attachment 33429
Ah I missed the one above your red line.
There is another, similar but different, if you see what I mean, much further down the page that is also illegal.