T10-13BW Bright White 13 LED T10 socket. This light is a Bright White 13 LED light that fits in a T-10 socket. This light is polarity sensitive which means it may need to be turned 180 degrees in the socket to work. This T-10 replacement light will replace a 194, 168, 921 bulbs if there is enough room for the LED part of the light. See pictures below for measurements.