This door would work fine to keep out unwanted cats, but anything with the dexterity of a raccoon can get through. The problem is that the magnetic catch only works for the inswing. Raccoons can grab and pull the door open, if they're clever enough. It took my local raccoon 3 days to figure it out, and now it might as well be a normal cat door. The only way to seal them out with this item is to lock it down completely, which you can of course do with a regular cat door.Also, the door needs a hole cut an inch more than should be necessary due to inefficient screw and mechanism placement. Wouldn't be a problem, but I was using an existing hole made for a more efficient door, and had to modify the housing and the screw holes to get it to fit (which the designers of this item could and should have done).