Rock Solid Cross Bar Side Arm The cross arm side arm mounts to any column with a 3/8" thread Add a Rock Solid Tripod Cross Bar to create a Tether T setup providing a height variable solution for step and repeat and portrait photographers Two 3/8" male threads for mounting ball heads, flashes, or other accessories Adjustable sliding middle connection features double locking ratcheting knobs. This listing is for a Rock Solid Cross Bar Side Arm and carrying case. All other items pictured are also sold separately.