The Vanguard Multi-Mount 6 Tripod Utility Bar is an accessory that allows you to mount two cameras or other devices such as a flash units, spotting scopes, or tripod heads to a single tripod.
The bar attaches quickly and easily to your tripod with a 1/4"-20 or 3/8" threaded screw via the included adapter. Adaptors are also provided so that you can and can either screw size to attach your camera, flash, spotting scope, etc., to the Multi-Mount 6's sliding bar heads. At the each end of the bar there is a 3/8"-16 screw for attaching a ball head or pan head.
This handy accessory is well suited for a broad range of shooting situations. It is great for wildlife or bird photographers, for example, who want to mount a spotting scope and a camera on one tripod for finding one of nature's creatures in the wild and then capturing an image of it before it walks or flies away.