Plastic mounting plaques for orchids

[Hien]

I want to change to mounting all of my dendrobiums (instead of in pots)
so I can clean them . With mounting, I can turn the dendrobiums upside down
and wash the underside of their leaves .
I have seen the plaques before but not much about the sources.
they are about 3" by 7"
Does any one know the manufacturer? sellers ?

 

[eds]

If you're struggling to find them maybe filter grid cut into the right sized pieces may also be an option?
https://www.koilogic.co.uk/filter-media-grid/p656