The top crossbar on the AquaVault server as an accessory platform for lighting and/or viwefinders you may wish to add. The knobs that secure the weights to the crossbar use 1/4-20 theads, the industry standard thread for photo equipment around the world. These knobs may be used as "clamps" to hold almost any lighting that utilizes a flat plate and clearance hole mounting.
In addition, a 1/4-20 threaded hole is located in the center of the crossbar for affixing a viewfinder, hot shoe or other after-market accessories.
An accessory plate and knob adapter may also be purchased from Atmo-Seal to mount lighting that utilizes a 1/4-20 threaded hole.