CLK is a compact clock generator with controls suitable for a master clock.

The range of clock speed can be switched with the RANGE switch, and "SLOW" in the left position controls 34 ms-10 seconds, and "FAST" in the right position controls 8.5 ms-2.44 seconds with the RATE knob. RATE can also be controlled by voltage, and PAUSE, which suspends the clock, is controlled by a button and a gate (inputting the gate toggles Pause on / off).