Microtuner
A microtuner or microtonal tuner is an electronic device or software program designed to modify and test the tuning of musical instruments (in particular synthesizers) with microtonal precision, allowing for the design and construction of microtonal scales and just intonation scales, and for tuning intervals that may differ from those of common Western equal temperament. The term also indicates a high-precision mechanical tuning device found on some vintage Conn brand brass and reed instruments (mostly cornets and alto saxophones).