The only thing I know about this meter I also got from Rene, is that it is really big and heavy. (28 x 20 x 8 cm) made from 2mm steel plate. It is well made. The switch is a very nice ceramic version and a treat to use. It measures AC and DC voltage and current.
It has a resetable fuse. That is the small red pin left above the range switch. It looks like is was rack mount. The top connector is not electrical connected to the meter. It is probably only used for mounting. There is a little plate on the side that reads MG / VA ( probably German for Mess-Gerat Volt Ampere) DY1013.
The underside is open. We think it was made for educational use.