The WEST MARINE Festoon 39mm LED Bulb has been designed as a replacement and upgrade for standard halogen, Xenon and incandescent filament bulbs, offering dramatically lower power consumption and heat generation, while having much greater lifetime and shock resistance. For even greater light output and quality as well as higher efficiency (more light per watt) please look to our Premium series bulbs. This bulb replaces and has similar brightness to 3 to 5 watt Halogen/Filament Festoon bulbs. Fits many 36-41mm sockets. This is the standard length festoon. 11-14VDC input range. Cross reference #'s 3910, 3423, 3425, 6411, 6423 6461, 3710, 6418, 6486X, 6461, 6418LL. 65 max lumens, radiates to one side of the fixture. Commonly used in automotive, marine and RV dome and interior lights, companionway lights. Lower power and brightness replacement for Perko 0070DP0CLR and 0069DP0CLR for non signal applications. Premium version, model #18592634, of this bulb puts out 2.5x the light and replaces 10 watt bulbs, OE Perko 0070DP0CLR and 0069DP0CLR, with the exception that it only shines in one direction. Note this bulb is polarity (+/-) sensitive, if it fails to light when inserted into the fixture, remove the bulb, flip 180 degrees and re-insert. Dimmable.