It is knock monitor. Brand new. Hand made. Very bright LEDs. Mounted in a plastic box. It is clear when light off.
It is hard to miss detonation signal.
Dimension: 65mm x 50mm x 20mm (L x B x H) exact dimension may vary.
Weight is ~100g

Wire length: 1.5m . 

You can choose other combination of led color of green, blue, yellow, orange, red. (detonation signal  RED ONLY).

Analog output is added by default. You can use output of monitor as input to your ECU to manage ignition or fuel if you ECU has AUX input.  Also possible to use with ignition controller.

Output 0+5V is default option.
Let me know if you need other type of output.

Shipping cost included.