Hi
I've just bought one and it's fab. You set the flap in 'memory' mode and encourage the cat to put it's head towards the flap. It registers the microchip in the back of the cats neck and then unlocks the flap (inwards only)
It can register up to 32 different cats microchips
The flap makes a slight click when unlocking so can unnerve a cat to start with.
I bought the Sureflap one as it has excellent reviews and we wanted a battery operated one. The Petporte one works from the mains I believe.
We paid £69.99 for ours direct from the supplier. Very pleased with it :thumb:
ETA - oh, just saw you wanted it for a rabbit. Can't see that it would make any difference though to be honest but why would you want one for a rabbit ? I don't see the benefit ?