Equalizer® JetPacks™ vacuum cups eliminate the need for manual pumping. If the cup loses vacuum, the AIRFORCE™ vacuum technology takes over and keeps that valuable suction going until the cup has maximum vacuum again. Equalizer® JetPacks™ have a 7" diameter cup with a maximum safe working load of 100lbs/45kg. They will fully charge within two hours. The single cup comes with one 120 volt charger and the pair come with two 120 volt chargers packaged in a soft carry case.