TuneLab Piano Tuner is a professional tool designed for piano technicians to achieve precise and custom piano tunings. Developed by Real-Time Specialties Inc., this full version app has been a trusted choice for piano technicians since 2001.

With an impressive accuracy of up to 0.02 cents, TuneLab Piano Tuner utilizes the inharmonicity of the piano to construct a custom tuning. It also offers an over-pull mode for more accurate pitch-raises. The app allows for the storage of hundreds of tuning files for individual pianos, which can be stored locally or in the Cloud using Dropbox.

One of the standout features of TuneLab Piano Tuner is its support for historical temperaments for period music. Whether you're working on classical compositions or modern tunes, this app has you covered. Additionally, the app automatically switches notes as you play, providing a seamless tuning experience.

TuneLab Piano Tuner offers a strobe-like Phase Display for fine-tuning, as well as a versatile frequency spectrum display. The Phase Display features a band of black squares that move left or right depending on the sharpness or flatness of the note, while the Spectrum Display graphically represents the frequency spectrum of the desired note. This combination of displays allows for a more comprehensive and accurate tuning process.

Overall, TuneLab Piano Tuner is an indispensable tool for professional piano technicians. Its ability to create custom tunings based on inharmonicity measurements, support for historical temperaments, and intuitive displays make it a must-have for any piano tuning professional.