I went to Icecaps site and kretzkiller and jthomps123 are right. I copy and pasted this straight from Icecaps website.
Along with the 430 model, IceCap fluorescent lamp ballasts have been the industry leader for nearly twenty years. Rugged, reliable, and efficient are just some of the many accolades for this category classic ballast. The 660 can drive all VHO, PC and T5HO lamps in any combination up to 4 lamps, with a total not exceeding 440 Watts. It is fully dimmable when driving VHO lamps, operates silently, and is fully repairable with a 3-year warranty. It is a high frequency solution for aquarium, industrial, UV, germicidal, and horticultural applications.