B Augmented Major 7th, 2nd inversion (G in the bass)
Also written as Baug(maj7)/G.
Notes, from the bass up
G (bass)A#BD#
The same notes as B Augmented Major 7th (G, A#, B and D#), rearranged so G is the lowest note. Use it to move between chords with smaller jumps across the keyboard.