My Omega B-8 uses the still-made, but somewhat uncommon PH 111A bulb. I'm still using the same bulb that came with the enlarger when I bought it used in 2006. I have about a dozen spares. I also got two extra Omega B lamphouses so that I'd have spares of the discontinued bayonet socket this bulb uses. I'll be 69 years old in a couple of weeks. I don't think I'll have to worry about running out of enlarging bulbs; I wouldn't even have to worry if I were forty years younger :-)