Electrically: The PR-43 refractometers are not interchangeable with any other refractometer model. All PR-43-AC/AP refractometers are however interchangeable with each other as long as they have the same prism. The PR-43-AC/AP refractometers are not compatible with the indicating transmitters DTR, STR or IT-R.
Mechanically: The sanitary process refractometer PR-43-AC/AP fits the same sanitary process connections as PR-23-AC/AP.