These Pin Mount™ transport tanks are a 'one of a kind'. Trust me, there is a valid reason for that. Unlike the traditional hoop systems that have been used for years, the Pin Mount™ system doesn't require a frame around the tank to secure it. Instead, it uses a steel pin through a molded hole in each leg. These pins then bolt down through the trailer bed. The Pin Mount™ system is less expensive, more secure, and also eliminates wear points on the tank that occur with the hoop system.