2" Round Diameter Universal Lighting Cross Bar 5 FT Attaches To 1 3/8" 35mm Stand

The ProX XT-5FT-TRBR 2 Round Support T-Bar is designed to mount on top of a 1 3/8 spigot-equipped stand and to support your lights or accessories. The bar is 1. 5 Meters 5 foot (59. 5) long, allowing enough room for four focusing ellipsoid or par lights or even a pair of speakers when used on a stand of adequate support capacity.  

Utilization of heavy-duty 2 clamps will increase the stability of your fixtures...
https://www.proxdirect.com/products/view/1331