I have this
http://www.harborfreight.com/single-...sor-43753.html
and (similar to) this
http://www.harborfreight.com/macpher...-set-3980.html
They both work. The clamshell style is less bunglesome, and seems more secure.
Tip: grease the threads for longevity.
Last I checked, Autozone had the dual screw type as part of their tool loaner program.