This was a really neat idea! Didn't work so great for our puppy, though. She was too rambunctious and didn't want to sleep. Had to stay up with her late at night and the only way she'd go to sleep for the first week is if I was holding her or had my hand in the box we kept her in at first. Might work for other puppies, though. Heartbeat sound beats for about 2 minutes or so after it is initially pushed.