A company sells a conversion kit that can convert commercial trucks to hybrids. The kits primarily consist of an electric motor that attaches to the drive shaft, various battery options, and a controller. David Cloud of NetGain Motors explains that the electric motor kicks in during acceleration. This results in "20% better fuel mileage" according to Cloud. The target market seems to be UPS-style package delivery trucks. Pricing can be found on NetGain Motors' website.