The Stack Module holds two additional drums to double the system capacity for a load of 1500 lb (680 kg). When storing both 30- and 55-gallon (110- and 200-L) drums, the smaller drums should be placed on the top of the stack module.The drum Management System is a space-saving, stackable design that stores up to four 30- and/or 55-gallon (110- and/or 200-L) drums of Class 1B or 1C flammables and combustibles or nonhazardous liquids. 100% molded polyethylene construction provides maximum chemical