Note recognition trains your ear to identify specific pitches without a reference. Start with natural notes (C D E F G A B) on the Natural difficulty, then add sharps and flats once those are solid. The "With octave" mode adds the octave number for musicians who want to develop absolute pitch awareness.
Combine with the interval trainer for complete ear training. After each session, practice on your instrument by picking out melodies by ear — the training only sticks when applied. Set a practice timer at timer-hub.com and target 10 minutes per day.