This item came really quickly considering being so close to Christmas. We couldn’t wait to let our labrador open it on Xmas day. He hasn’t quite grasped the concept as yet, as he likes to pick it up and take it on his bed. I don’t think he would do this with a larger one, so we will be purchasing one when they become available. It extremely easy to use, unlock and fill. There is plenty of room for various sizes of treats and there is a good range of movement from easy to hard. They lock well and, so far, I haven’t seen any damage or damage to our wooden floors. I highly recommended this product to help stimulate your dog and it’s a good bonding toy for you and your dog too!