It has the same design as the Ebonite four ball in line roller with the exeption that the hammer bag has a better color scheme and the handles are different. The extra spot for the fourth ball is where the shoe compartment is on the Hammer three ball roller. They somehow made it so that they did not loose any storage space for shoes or accesories. It's a great durable bag and both the Hammer and Ebonite version will be out the first week of April.