Here are a couple of tachometer styled transistor radios from the 1970s, part of a short-lived trend for novelty radios.
Panasonic Model R12, 9 volt AM band portable radio.
Sanyo "Tach rad" Model F-8410R, AM FM band intended to be permanently wired into your car and mounted on or under the dashboard. This item was found on Kijiji Toronto.