This Ancor Marine Grade 1004 Series Double Contact Bayonet Base Mini Lamp is ideal for marine navigation or interior lighting systems utilizing BA15d sockets. The 12-volt, 12-watt miniature incandescent lamp is designed for high corrosion resistance, featuring a durable glass bulb and nickel-plated brass base. Each pack includes two lamps, providing an efficient solution for lighting replacements on boats. These new old stock (NOS) lamps are unused but may be in aged packaging, perfect for those seeking hard-to-find replacements. Ancor part number 521004, with an alternate listing for Sea‑Dog 441004‑1, ensures you're getting certified quality fittings. With dimensions of approximately 1.25 inches height by 1.85 inches width by 4.94 inches depth, these lamps are compact yet essential components for reliable marine lighting.