The Beta Tools COMBO C99 Modular System is comprised of three different types of tool cases. The system is designed to allow users to combine and easily transport different types of tool cases. The tool cases are easily joined to each other by a simple click via the functional side snap-on mechanism. The tool cases are made of sturdy, shockproof ABS and provide an internal load capacity of 55 lbs and bear up to 220 lbs of weight on the lid. The system also includes a wide range of accessories such as hard thermoformed trays, tote trays with removable partitions, small parts boxes with transparent covers, and soft foam pre-cubed inserts.