Air boxes, also known as air filter housings, enclose the engine air filter and provide a sealed intake pathway to the throttle body. Typically constructed from durable plastic or composite materials, they protect the filter from debris and moisture while minimizing air restriction. Internal baffling and ducting within the air box promote smooth airflow and even filter utilization. Designs vary to accommodate specific engine layouts and airflow requirements, often incorporating mounting points for air intake ducts and sensor integration. Secure sealing to the throttle body is critical for maintaining proper air/fuel mixture and preventing unfiltered air entry.