250 Watt Halogen Quartz bulb (bayonet style base) May be used with retired Zeus standard and Bi-tube heads Lifespan dependent upon proper handling, power levels and frequency of use The Einstein flash unit's modeling lamp is user-replaceable and comes with replacement instructions. The modeling lamp for the Einstein flash unit is user-replaceable and arrives with instructions for replacement. *It is not necessary to purchase a modeling bulb separately when you are purchasing a flash unit however it is never a bad idea to have a spare on hand as a back-up in the event of breakage. Please note to always wear gloves when handling the bulb as the oils from your hands may damage the bulb, shortening its lifespan.