4 post car lift power units use either a 110 Volt or 220 Volt electric motor. Mr. Homeowner’s hobbyist four (4) post lift (portable) requires a 110 Volt electric motor power unit and the commercial grade professional 4 post car lifts use the 220 Volt single phase electric motors. We stock both styles of Atlas® power units. The size of a lift’s cylinder will help to determine the size of oil reservoir needed.