This is one of the strongest, high-quality units you’ll ever own.  The Smith-Victor ArmBar mounts onto the center column of tripods with 3/8″ threads. The platforms feature 3/8″ screws, which allow a standard tripod head to be mounted on either or both sides. In addition, the horizontal bar features 3/8″ screws on both ends, allowing mounting of tripod heads from the sides. You’ll know it when you feel it–pro quality all the way through.

-Four 3/8″ mounting plates, two adjustable.
-Mounts securely to a 3/8″ tripod with dual-locking head.
-Use as an extension arm or a base for lighting equipment or monitors/laptops
-Knurled plates for quick and easy mounting of your gear
-Supports up to 22 lbs
-Includes carry bag

This is a must-have accessory if you’re getting the tether tray! Tether Tray Heavy Duty Laptop Tray