The Zacuto Z-ZRSM Z-Rail Slide Mount clamps onto Zacuto's standard Z-Rail and tightens with a quick release ratcheting lever. The Z-Rail is part of most of the camera top handles and the EVF Top Mount. The Z-Rail Slide Mount can clamp forwards or backwards and slide up and down the Z-Rail for balance and accessory placement.
It has a threaded rod port and can accept a Zacuto 15mm male rod. This allows you to attach a rod set at a right angle to the Z-rail. You can attach two Z-Rail Slide Mounts to a Z-Rail and set the rods to lightweight or 15mm studio spacing over your camera lens to hold a follow focus and mattebox. Or, you can use the rod to hold a Zacuto quick release arm and accessory like Zacuto's Zound Rod which could hold a microphone, a light, or the EVF.
The top surface of the Z-Rail Slide Mount has a 1/4 20 tap for attaching a threaded articulating arm or accessory. You can attach the Z-Rail Coldshoe for any hotshoe accessories.