This Novatron 60V4002C 2 Head Mini Pro Kit provides 400 watt/seconds of stored power. The V400D is one of Novatron's most popular power packs. It features 400 w/s of infinitely variable power, plus an adjustment range of 2 f/stops, marked in .5 stop gradations. This extra adjustment feature is especially useful when using a digital camera. The power pack is small, economical, and best suited for passport and school photographers.