WJ 4U, 6U, 9U, and15U 600mm depth simple racks are built with high-quality aluminum/steel structures and are ideal for countertops or under deskapplications. These units are lightweight, stackable, and completelyportable; therefore it is easy and simple to stack up an additionalsystem when more space is needed. Running out of rack space may neverbe an issue again. With spring loaded recessed handles and casters(Casters Included), these simple server racks provide your criticalrackmount equipment the ultimate mobility and maximum portability.