The range of DOPAG grease pumps is designed to feed all types of greases from open-topped containers between one liter and 200 liters in capacity, cleanly and directly from the original containers. Each grease pump is mounted onto a twin post ram arrangement and is fitted with a follower plate that fits snugly inside the material drum, making certain that the grease cannot become contaminated during use. The follower plate also has the effect of wiping the sides of the drum clean that leads to minimal waste grease. DOPAG grease pumps have proved themselves particularly useful as central material supply for multiple grease metering systems as well as being able to supply single stations. The grease pumps may be arranged in pairs with an automatic changeover system to ensure that production is not lost when a drum of grease becomes exhausted.