I recently purchased my 4th 1000w Digital Ballast by ReVolt from http://www.gothamhydroponics.com and I am very pleased. These ballast are made of high quality material, have 3 adjustable wattage settings and have a built in fan. They also produce a minimal amount of heat. They are actually cool to the touch when running.

For more information visit:

http://www.gothamhydroponics.com/grow-lights/ballasts/hps-mh-switchable-ballasts/1000w-digital-ballast-revolt.html