This 2 Pack LB4000 Replacement Bulb is compatible with Germ Guardian AC4825 AC4850PT AC4300BPTCA AC4300BPT AC4850 AC4900 AC4900CA AC4800 AC4900 CDAP4500 AC5300B AC5350B AC5350W air purifiers. It is a UV-C Ultraviolet bulb with a G23 2pin base type. This bulb is a great replacement for the 5W UV-C Bulb. It is easy to install and comes with two packs of bulbs. It is not a Germ Guardian brand lamp, but all Germ Guardian brand names, trademarks and logos are property of Germ Guardian. Get this 2 Pack LB4000 Replacement Bulb for your Germ Guardian air purifier today!