digital ballasts

Another great feature of digital ballasts is the ability to run both
MH and HPS bulbs on the same ballast without having to flip a switch
(it should be noted that not all digital ballasts on the market are
programmed (or optimized) to do this properly, Eclipse LED digital
ballasts are). Research shows that Eclipse LED ballasts are optimized
for the most efficient HID output available. Our digital ballasts are
designed to give you maximum light output at the best efficiency
possible. Compare the Eclipse LED digital ballasts with similar
wattage magnetic ballasts.

http://www.eclipseledcompany.com/Digital_Ballasts.html