the tonic triad
the mellowed supertonic triad (♭)
the mellowed supertonic triad in its first inverstion
the root is D♭
The triad root (D♭) is now a 6th interval above the lowest note (F). It is referred to as a ♭II6 triad.
The triad is much more coherent if you listen and understand the context in which the chord appears. It’s usually part of a chordal sequence. In the video, you will see and listen to the following chordal sequence: ♭II - i64 - V - i
Below, you will see two sets of chordal sequences, the second sequence omitting the i64.
Study the following two sequences. You might be able to understand the chords better by playing them on a keyboard or by listening to them. The key is C minor.
Try this one too.
Click on the video below to hear a clear example of this chord. It comes from the first movement of the Piano Sonata no. 14 in C# minor, op.27, no. 2 by Beethoven (Moonlight).