does anyone know where i can get a cat hood for grooming?

i have heard that you can get cat hoods to calm a cat down whilst grooming my boy scruff will not let us brush him, he came to us as an older cat who had never been brushed as a youngster, he has been to the vets to be dematted under anastectic a few times, this costs me about £100 a time and he has to go through the trauma of having to go to the vets and a couple of days to get over it i manage most of his matts with cat shavers but at most i get about 1 minute at a time, his knots seem to appear over night, someone told me that a cat hood will keep them calm whilst clipping him, i have search the internet but cant find them maybe they have a special name, i cant find them if anyone knows where i can get one to give it a try it would be appreciated, thanks