Various storage units that stack with other units, such as in a modular system, are provided. The storage units couple within a modular system via coupling interfaces on the top and/or bottom surfaces that couple the storage units to other units in the modular system. The storage units include a cover and a latch, the cover restricting one or more drawers from being opened. In a specific embodiment, the cover is slidably stored within the housing of the storage unit. The storage unit includes one or more internal storage compartments defined at least in part by the one or more drawers.