Simply draw a sample from the sump and inspect it in the upper sampling cup. Transfer the fuel to the lower catch can by tipping the sample cup in any direction. The MultiSump can check up to 8 sumps before needing emptied. Measures 7" h x 2 3/4" dia. Optional fuel strainer snaps onto the bottom of the MultiSump and utilizes a micro-mesh stainless steel screen to keep impurities and water from entering the fuel tank during pour back.