As you learned when you started out servicing air conditioning units, a vacuum can be hard to create. When you need to completely evacuate a system, the two-stage vacuuming of Robinair pumps comes in handy. The second stage of a Robinair vacuum pump action operates at a lower pressure in order to achieve a deeper vacuum and pull out the last straggling air molecules from a system. Besides its high vacuuming power, this pump has a die-cast aluminum housing that makes it lightweight, yet durable. If you desire a very high suction power, you should get a Robinair 15600 vacuum pump. This pump has a motor big enough to generate 366 watts and sufficient power for a brisk vacuuming rate of 142 liters per minute. In order to maintain continuous power, the pump has a built-in check valve that prevents its oil from being sucked back into the vacuum created. With the wide selection of high-performance vacuum pumps on eBay, you can find the best Robinair pump for your business.