vintage Stewart Warner 757W hand tachometer in tin case, 1940s garage or racing pit

vintage Stewart Warner model 757-W portable hand tachometer in the original storage tin. We've been told that this is probably from the 1940s. It will display 0 to 4000 RPM and is in nice working condition.

This measures about 2 7/8" across and 2 1/2" across the gauge face. It is very clean with just a little wear to the tin case.