I have a long haired cat (Cat 1) and he doesn't wear a collar - my cats are microchipped so they don't need to wear ID tags. They used to have collars with magnets so they could get in the posh catflap but Cat 2 nearly hung himself on the collar (it's not uncommon apparently to get them caught on branches etc., mine got his collar caught on the handle of the window when he was looking out) so no more collars for me. Cat 3 used to get inside his collar and wear it like a bandolier slung over one shoulder, when I used elastic collars for safety, so that didn't work either. I don't recommend them at all for security and safety (and they don't need one to look pretty either!).