Includes bulb and socket assembly with red and green bulb coversOne of the most requested line additions in AutoMeter history, this Mechanical Exhaust Pressure Gauge has been engineered to the highest standards of accuracy and durability. Precisely monitor your exhaust backpressure to maximize power and efficiency and ensure turbo longevity. Also ideal for cam tuning, a simple 1 8" NPT connection is all you need for installation. An install kit with 1 4" copper tubing is included and an optional particulate filter