The kit consists of a 5kWh battery pack filled with A123 lithium ion cells that fits into any second-generation (2004-2008) Prius. The pack can be fully charged in 4.5 hours at 110V and Hymotion claims a converted Prius will get up to 100mpg for 30-40 miles. Your mileage will of course vary. The pack has been crash tested and meets all current federal safety standards. Hymotion was bought up by A123 last year after doing a number of conversions for fleets and government testing.