This extremely robust, double-walled training buoy is primarily designed as a large surface buoy for freediving. It can also be perfectly used for marking during scuba diving or in any situation where a large buoy with storage space and handles can be useful. With a durable outer shell made of Cordura and a separate inner bladder made of polyurethane, which is available separately. It features a large interior compartment, for example, for transporting the buoy line when not in use, with a zip cover, four external handles, and two D-rings complete the equipment. It can be inflated by mouth or with an inflator hose and has a pressure relief valve. A stainless steel D-ring at the bottom of the buoy allows for the attachment of the freediving line. Integrated flag.