KLINGER SCIENTIFIC / NEWPORT CORP. BG120 GONIOMETER +/- 45 Degrees 120 MM WIDE.
/100 ( 354-511 ) and 1 deg/1000 ( 354-512 ). The difference is in the encoder. I don’t know which model this is, there are no model no. or other external markings, except for the serial number. +/- 45 degrees travel.