I have both. The cat flap to go into the run and the runaround door for the tunnel onto the lawn (shut off at night) . 4 of my 5 bunnies can use the cat flap, but Dave has not worked it out yet so Ive had to tape it open. It's quite new so hopefully he'll learn. The positive thing about the cat flap is that it keeps the drafts out (unless it's held open by tape so that silly rabbits don't get shut out in the cold run...)