There are a number of different lamp types and fittings, which are often specific to one type of heater , although there may be different types of lamp available for the same heater housing. Please select carefully; if in doubt, please ask.
Lamps are often available branded, eg 'Philips', or as a generic unbranded product. In our opinion, the price difference does not always justify the difference in cost. Burda lamps, however, are very expensive but standard lamps will not fit.