Dual Speaker Bracket Pole Mount for Speaker Stands

The ProX X-DS29 safely and conveniently mounts two speaker cabinets to one speaker stand. Constructed from steel, this bracket mounts to most standard speaker stand shafts. It features standard 1 3/8 inserts and a black powder coat finish.    This bracket will allow mounting of two 10 or 12 speakers on a single stand.   Caution: Do not exceed safe loading weights and always protect the stand from tipping...
https://www.proxdirect.com/products/view/218