JohnDow JDI-20COMBO 20-Gal Combo Fluid Evacuator & Oil DrainJohnDow JDI 20COMBO Combination Fluid Evacuator & Oil Drain 20 Gallon Capacity This all in one fluid evacuator and self evacuating oil drain gives you greater functional versatility when handling fluids in your shop. Using compressed air, the venturi pump creates a vacuum in the steel tank. The easy to read vacuum gauge lets you know when you achieve the proper suction level. This is literally the only oil drain or fluid evacuator you will ever need.