Since the Prius doesn't have a starter motor, I wanted a set of really light duty jumper cables.  I got this instead.  I figure I won't need much charge to light up the dash and get the car running, should I run my battery down.  However, a friend brought up one caveat, which is that with keyless ignition, one can't always go power plug to power plug.  So I got a set of these http://www.amazon.com/gp/product/B00065L2D8/ref=cm_cr_ryp_prd_ttl_sol_19 to go with this device.  They are a nice set of light duty battery clips - perfect for the little battery in my Prius.