it is of no use at a low idle...it doesn't register well (accurately)at 1200 rpm or below...and when it does read accurately higher RPM its location makes it impossible to accuratly read unless your willing to lean over it, or it is near the "12 o'clock" needle position (not a good plan when under way) so your left to glance quickly, at the wrong angle, and guestimate your RPM...why bother Drag specialties makes one that others have purchased and mounted up near the speedo (a MUCH better location) that is more accurate at lower RPM...IE the "tunning balancing range"...at least thats MHO
