Auto Meter 4532 Ultra-Nite Water Temperature Gauge Luminescent dials glow green at night for dimly lit tracks when no battery is available to light conventional instruments For racing use only - Not intended for street applications No electrical system required for gauge operation - compatible with every street or race vehicle Auto Meters race proven mechanical instruments provide trusted accuracy and durability in the harshest environments while being simple to install Gauge kit includes 1/2" NPT adapter, bulb and socket assembly, red and green bulb covers, mounting hardware, and detailed instructions for installation