Auto Meter 8404 Factory Match Mechanical Boost Gauge Factory matched LED through-the-dial lighting provides clear visibility during nighttime use and matches OEM instrumentation 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 Mechanical movements provide accuracy and durability even in the harshest environments Gauge kit includes 1/8 nylon line, 1/8 NPT compression fittings, 1/4 NPT adapter, mounting hardware, and detailed instructions for installation