Big enough to hold a plastic water bottle, a couple of tennis balls, some old socks. The Bottle Tracker Toy can be used for retrieving, scent recognition, search & rescue training, and contra-band training. It also makes an enthralling and interactive toy. Fill a basic plastic bottle, which acts as a barrier between the scent and the toys’ inner surface, with training treats, ice, or scenting materials and add a few holes for the scent to escape. Made from tough, pre-consumer recycled fire hose material, this toy has a Velcro sealed compartment for enclosing the bottle and a sewn in loop for tugging.