 They are physically connected either to the counterhoop, in which case the gauge indicates how far the counterhoop is pushed down, or the pedal, in which case the gauge indicates the position of the pedal.These gauges are accurate when used correctly.However, when the instrument is disturbed in some fashion (transported, for example), the overall pitch can change, thus the markers on the gauges may not remain reliable unless they have been adjusted immediately preceding the performance.