I fitted a cat flap when we first got Amber and Milo, one which is activated by the magnetic tab on their collars. After a few weeks they both lost them, so instead of buying two more which at the time we could not afford I set the cat flap on open both ways. It has been like that for about 6 months or more. All was ok untill about 5 weeks ago when another cat was coming in and taking food, then it got to the stage that when it came in all hell broke lose. Last Friday was when we lost our baby Amber, so on the Saturday morning I purchased two more collars and magnets for Milo and Minnie Moo. This is the strange part, I have just come back upstairs to the computer after making myself a cup of tea and there in the middle of the floor is Ambers old collar complete with magnet. Since finding it I have been in and out of the room a couple of times and it sure wasnt there then.