If you want to keep it under lock and key this is your answer. The surgical steel collar and multi spiked inside make an EROTIC pleasurable experience. Not only can you lock it up but you can tighten down all of the allen keys one at a time to put him in a whole new place. And when and if you ever do let him out LOOK OUT! The Inside diameter is 44mm before the spikes and if the spike are all tightened it goes down to almost an inch. The weight is 38mm high and its is hinged and closed with a lock. The spikes can be adjusted to fit your pleasure level. The Toys listed on our site are for use by consenting adults only as either a Novelty Items or Sexual Toys. We assume no responsibility for Unsafe Improper or Illegal use of these items. Please be Safe Consensual and always use Common Sense!