AmericanDJ LL-F20BLB 20W Blacklight Replacement Tube

The ADJ LL-F20BLB is a 20W blacklight replacement tube, the consumable inside a UV fixture that eventually stops putting out useful ultraviolet long before it stops lighting up.

Blacklight output falls off with hours run, so a tube that still glows can be delivering far less UV than it did new. Swapping it is the cheapest way to bring a tired UV wash back. ADJ catalogues it under Replacement Lamps as part number LL-F20BLB.