This Lamp is designed with a 100 volt, 3 amp arctube for operating on a 250w HPS Ballast/Ignitor you can also get them for Mercury Ballasts they are known as Kolorarc the Code would then be KRC250/T/U/740/E40 this has a 130 volt, 2.15 amp arctube and a 4000 deg K Colour Temerature.
All the Best
Colin