Type B

The Type B voicing of Abm7b5 stacks Gb, Bb, Cb and Ebb from the bottom up: the minor 7th, 9th, minor 3rd and flat 5th of the chord. It leaves out the root, Ab, for the left hand or the bass player to take.

It's one of the 4-Note Rootless (Type A/B) voicings: four-note rootless voicings in their two forms, with the 3rd or the 7th on the bottom, played over the root. The other for Abm7b5 is Type A.