Vtg Weidenhoff 0-1200 Breaker R.P.M Gauge Zero Adjust Nice Condition

This is a hard to find RPM gauge by Weidenhoff 0-1200 Breaker RPM looks to be working but I have not tested this item.  The condition is nice I did take a couple photos so you can see.   The gauge is about 3" at the bottom and 2.25" at the top.