Harbor Freight has an 18V 1/2 hammer drill they run on special for $29.95 occasionally and I've found it to work really well. See it here:
http://www.harborfreight.com/cpi/cta...emnumber=91176 It even lifts the trailer a little. Somebody mentioned the 18 V Coleman from Pep Boys. I made the
big mistake of buying the whole kit with the recip saw and circular saw ($99). The whole kit is junk IMHO and you can't buy additional batteries. I finally found some that will work, but had to disassemble and add an additional contact to each one or the charger wouldn't charge them. I wouldn't give 2 ¢ for the whole kit. The battery is good for about one time of running the jacks up and down. The hammer drill from Harbor Freight is a lot better in my opinion and a battery lasts for 5 or six times. Extra batteries are about $16 and they have a button you can push to indicate how much charge remains. I use a 1/2 inch concrete anchor bolt from Lowes instead of the allen wrench because the allen wrench wears the hole out in the jack.