Contech SquirrelStop Automatic Spinning Squirrel Deterrent The weight of a squirrel on the feeder Starts the SquirrelStop spinning for 20 seconds causing the squirrel to jump off Safe and harmless to squirrels and birds Works with any hanging feeder up to 10 lbs. Easy to use - no assembly required SquirrelStop helps ensure you are feeding birds - not squirrels