Manfrotto 131DD Multiple Head Support Tripod Accessory ArmGood condition. This is a Manfrotto 131DD Multiple Head Support Tripod Accessory Arm. It has four heads and mounts to the center column of a tripod with 3 8" threads. The platforms feature 3 8" screws, which allows 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. The screws on either end have rubber removable protector