There were earlier makers and their plastic discs were approved by the CMCA. The current ones on the market are OK to use- but the drawback is the the length of the

boss (the centre piece with the hole) It protrudes too far which makes it difficult to pick up 3 or 4 discs in one hand at the end of each head. Bad design fault which should be rectified. They also don't sit easily when stacked.

Would like to find the makers of the earlier plastic ones..