Designed to mount on top of our standard 30- and 45-gallon (114- and 170-L) safety cabinets, these Piggyback cabinets create a safe storage space without taking up any valuable floor space. Cabinets can also be used independently as a wall-mount unit or on a countertop.Justrite Piggyback Hazardous Material Safety Cabinets have the same quality safety features as the cabinets for flammables. All models come with double-wall construction, dual vents, grounding wire connections, adjustable shelves,