Fotar ND filters?

[Squidy]

Hi all,

I ordered a Hoya variable ND filter and instead the company sent me a Fotar variable ND filter. Unfortunately I need it in 2 days time and there's not enough time together it exchanged.

I can't find much info on them, are they any good?

Also, just to add to this, should I take off my uv filter first? I'll be filming on or near the beach so I'm not sure what damage will happen ie flying sand when changing filter from one lens to another