Wires introduce an intrinsic 1 sample delay, or 1/48,000th of a second. Even accumulated delays are imperceptible for audio & performance purposes, but they can nonetheless affect audio-rate synchronization, create imprecision when simultaneity is required (for instance, the timing of two triggers to a logic gate), and so on.
This device measures the delay (in samples) between its four trigger/gate inputs, updating the results in white. The dials add compensatory delay, with updated output in blue. At the bottom, a reset button helps override windowing errors.
All you have to do is adjust the dials so that the blue readouts match, and you’re good to go.
It’s intended for pulses (gates & triggers), but it’ll also work with simple, standard waveforms.