The R/V industry has used 921 incandescent bulbs in ceiling lights for ages.
They look like this...
Most folks are replacing them with LED equivalents. (there are hundreds of options)
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2022 Cedar Creek 345IK 5th Wheel•Solar & Inverter•2017 Ford F-Series SCREW 4x4•Factory Puck•B&W Companion•TST Tire Monitor w/Repeater•Sinemate 3500w Gen.
F&AM Lodge 358 Somerset, PA - JAFFA Shrine - Altoona, PA
Days Camped ☼ '19=118 ☼ '20=116 ☼ '21=123 ☼ '22=134 ☼ '23=118☼ '24=86