Auto Meter 3803 GS 2-1/16" 30 in. Hg/30 PSI Mechanical Vacuum/Boost Gauge Modern green LED through-the-dial lighting provides clear visibility during nighttime use Auto Meters race proven mechanical instruments provide trusted accuracy while being simple to install No electrical system required for gauge operation - compatible with every street or race vehicle Gauge kit includes 1/8 nylon line, T-Fitting, vacuum fitting, compression fittings, mounting hardware, and detailed instructions for installation Mechanical movements provide accuracy and durability even in the harshest environments