#PR6 FLASHLIGHT BULB P13.5S BASE - 2.47 Volt 0.30 Amp B-3-1/2 Single Contact Miniature Flanged Base (P13.5S) C-2R Filament Design, 0.45 MSCP. 30 Average Rated Hours, 1.25" Maximum Overall Length, 0.45" Maximum Overall Diameter. Typically found in flashlights using two "D" industrial cell batteries. #PR6