Does not fit the Mtek FLUX helmets. While it's technically possible to attach the adapter to the MLok rail on the FLUX, this can only be done if you remove the rail from the helmet and attach it from inside the rail. Once this is done, the position cannot be adjusted. Furthermore, the position of the rails on the FLUX means that any hearing protective headsets will be mounted far away from the user's head (even in the tightest setting). Clearly designed for Exfil/Team Wendy style helmets. Packaging does not mention any compatibility with Mtek helmets, product description seen here is wrong.