LED 24CK retrofit" refers to a LED conversion kit designed by Tri Lite, specifically meant to upgrade existing incandescent "Stop & Go" signal lights used on loading docks, allowing you to replace the old incandescent bulbs with energy-efficient LED modules while maintaining the original fixture's housing and functionality. LED24CK 24 VDC can be used for Tri Lite models SG10-24RG, SG20-24RG, SG30-24RG