Lumatek 600W Electronic Ballasts are switchable down to 400W as well as having high frequency (Super Lumen) options for both. Lumatek is the worlds leading supplier of Electronic Ballasts to horticulture. With the arrival of Electronic Ballasts, a technological revolution has taken place in energy efficiency for HID lighting. This replacement of magnetic ballasts (a technology more than 100 years old) with electronic HID ballasts is because of the proven efficiency gains. Tests have shown that Lumatek E-Ballasts are up to 30% brighter than some old style magnetic ballasts. Independent laboratory tests have proven that Lumatek E-Ballasts are more efficient than any magnetic ballast known to Lumatek. This means more lumens are produced per watt of energy consumed.