5/32 (4mm). Mounts to the rocker box and adds a visual pressure check to your suspension system. Works with all air suspension systems. Allows quick and precise adjustments without guessing. Includes a white face 1.5" 160psi air pressure gauge, one T fitting and one elbow pressure line fittings for a 4mm (5/32") pressure line and a steel gloss black powder coated rocker cover bracket.

Fits: > 99-17 Twin Cam (NU), 17-21 M8 models with any air ride suspension system