My apologies. We tried to look-up this info from Challenger's site, but they don't have it posted. We emailed our Challenger rep multiple times requesting this info to no avail. I'm telling you this so that hopefully you understand our inability to answer your question does not stem from Redline's attempt to do so. My apologies, but we recommend you consider a different bridge jack. Maybe consider the RAJ-7K by Kernel Manufacturing. We like selling their jacks because customer service and parts availability are no issue with their products. Thanks for shopping with us!