iTuner is chromatic tuner application for iPhone, iPod touch, and iPad.
With needle metering, and scale / sharp / flat indicators, you can use this app for tuning your various musical instruments easily.

Reference Pitch: 435Hz - 445Hz
Detection Pitch Range：C1 (32.70Hz *) - B5 (987.77Hz)

This app includes advertisements, but you can disable them by using In-App Purchase.

*Low-frequency accuracy is slightly inferior