To use an oil dispenser, you first have to get the oil out of the original container. Prior to selecting a pump or cartridge system, you should decide how the oil will be purchased. Common containers are: 400 lb. barrel (55 Gallon), 120 lb. keg, 35 lb. pail (5 Gallon), 18kg, 25kg, and 35kg. We have single and double post ram pumps for the USA and metric size containers.