MaxPar has combined a ""DE"" 400V 2100 umol arc tube with a standard E25 mogul base lamp envelope which can be used in conventional fixtures. The 400V high-pressure arc tube in this lamp is designed to be used with ballasts that are rated in the market as ""DE"" ballast with an operating frequency between 85-115 kHz. Traditional digital ballasts will also operate on these lamps with no lowering of the output performance but possibly a shorter lamp life. If the lamp is replaced within the industry recommended norm of 10 to 12 months, the shorter lamp life encounter by running on a 35 kHz frequency will NOT be a factor.