These bulbs have 18 cool-white LEDs arrayed in 6 planes for 360 visibility, as well as 3 LEDs at the top. Proprietary constant current chipset results in high performance across the entire 10-30V DC range.

The cool white version is ideal for masthead (anchor light) and stern lamp applications in fixtures that use a BAY15d bulb (double contact, offset pins). It fits Aqua Signal Series 40, 41, 42 and 50, as well as Hella 2984 and Perko 200 Fixtures (clear lens fixtures only).
The ILTW1157-SMC replaces Aqua Signal bulb #90005, Hella bulb #78290 and Perko bulb #037512V10W.

Cool White is recommended behind clear lenses because it has a higher luminous output than Warm White. Because LEDs have a narrow spectrum, we don't recommend using Cool White behind colored lenses, as the colors will not be true.
Only use colored LEDs in navigation fixtures with colored lenses.