Electromechanical counters and electromechanical timers typically accept electric or electronic inputs to operate a mechanical display, such as rotating wheels or knobs.
A counter is a complete instrument for detecting, totalizing, and indicating a sequence of events.  A timer is a device for automatically starting, or stopping a machine or other device.  Many of these instruments can perform both counter and timer functions.   Electromechanical counters and electromechanical timers can be either single function or multi function, or programmable for more than one function.  Electromechanical counters and electromechanical timers can be up direction, down direction, or bi-directional.  Up directional counters can advance forward (UP) in its counting sequence.  Down directional counters can advance backward (DOWN) in its counting sequence.  A bi-directional counter can advance forward or backward (UP or DOWN) in its counting sequence.