piano chord
B♭m6
B♭1D♭♭3F5G6
A minor triad with a major sixth added, which is why it is not simply a minor chord with a flat seventh.
Written the other way round it is A♯m6 — the same twelve keys on a piano, a different piece of notation.
What is true of it
B♭m6 is B♭, D♭, F and G — 1, b3, 5 and 6 counted from B♭.
These are also the notes of Gm7♭5/B♭. Which name is right depends on what is underneath and what came before — the notes alone do not decide.
On an instrument that cannot reach all 4, the 5 goes first, in that order.