This LED bulb is specially designed as a direct, one-to-one, replacement for the incandescent navigation lights available on the market such as those from Perko and other manufacturers. One-to-one replacement for: Perko Bulb Fig. 337 Trade #68, #90, #94, & #1004 bulbs. Bayonet 15mm double contact non-index baseFor 2NM Nav lightsConformal coated & use of long life componentsConstant energy consumption, regardless of voltage fluctuationsLong life, shockproof, ultra-ruggedVery low power consumption