Car on the ground - measures chassis height directly, accurate to 1/16".
Car on scale pads - measures from top of pads - ground level - to frame directly (no subracting needed here).
Measures chassis height dynamically, as you work on the car. Magnet holds tape to frame. Indicator shows height as the car moves up and down. Use set of 4 to quickly see height at all 4 corners. You don't even need to bend over.