Spectre's 4 inch outside diameter - 18 inch long mass air sensor tube is designed for custom air intake systems utilizing 4 inch tubing and require the use of a blade-style mass air flow sensor. The welded on MAFS pad is designed for the GM and Fordblade style MAFS. Available with a polished aluminum finish, this tube can be welded or connected together to fabricate an intake system for almost any application. 4 inch outside diameter, 18 inch long tube for custom air intake systems with 4 inch tubing. Has a polished aluminum finish, and can be welded or connected together to fabricate an intake system for almost any application.