PR4 Standard Flashlight PR Replacement Light Bulb: Description - Standard replacement flashlight bulb - 2.33 Volt - 0.27 Amp - B-3-1/2 Single Contact Miniature Flanged Base (P13.5S) - C-2R Filament Design - 0.40 MSCP. - 10 Average Rated Hours - 1.25" Maximum Overall Length - 0.45 Maximum Overall Diameter - Typically found in flashlights using two "C" cell batteries.PR4 Standard Flashlight PR Replacement Light Bulb