This is a Volvo Universal Tachomter number VP 873 992, which is new in its box. It works with 12 to 24v supply, and will register up to 4,000 rpm.
It was manufactured by VDO Switzerland, and their part number is N - click here to reveal phone number - Date KW 05/97 The overall diameter of the face is 78mm, and the hole diameter needed for the body is 73mm. It comes with a red backlight push-in housing and a spare bulb. A bezel is not included with the meter, but is available from yachtboatparts at around £6.
Asking £70 ono. Could be posted at cost.