I don’t know if it is intentional or translation error. Their colour filters could be made of glass. If they are then their cost-cutting approach to packaging is to blame.
I noticed that it wasn’t made of glass, and get a rather disappointing 25-30% output drop with the diffuser on, although this is only around 15% if I remove the rubber casing and just hold the lense over the front instead, suggesting that a lot of the loss is light redirected out the sides of the lense due to the very aggressive diffusion properties. I much preferred the mineral glass one that came free with the Olight S65.
The packaging does also state ‘FILTER’ on it though, so it may just be a case of that diffuser having been sent in the wrong box. Unfortunately I threw my one away so can’t check that.
On mine, it’s like in the picture from FastTech, with additional NFD40 label at the bottom. So they print one card for four products.