The set consists of an accessory bar, a bottom plate, and two felt-lined split rings with a 1/4”-20 thread holes drilled and tapped into the center of flat bosses in the top and bottom of each ring to accept the accessory bar, bottom plate, and a stud or bolt as necessary for connection to a mount. This allows the rings to be used on a variety of equatorial mounts and mount adapters using standard 1/4"-20 mounting bolts. The individual rings can be spaced any distance apart or from 5.5" to 6.5" apart when the accessory bar and/or bottom plate are attached.

The rings are not hinged to swing open, but are in two sections that bolt together around the telescope tube. A no-tool bat-wing handle on one side of each ring clamps the ring firmly on your optical tube. A simple flip of the chromed bat-wing handles loosens the tube rings slightly to let you move the telescope tube back and forth in the rings to balance the weight of different visual and photographic accessories.

Each 4” i. d. tube ring has two dovetail grooves with #10-32 tapped holes machined into the top of the ring on either side of the accessory bar. These let you install optional TeleVue accessories on the tube rings, such as the StarBeam and Sol-Searcher finders, or a PiggyCam piggyback camera mount. The accessory bar itself has a variety of holes to accept a TeleVue Starbeam and other accessories and even a slot with which you can piggyback a smaller TeleVue refractor on the main scope. The included bottom plate (BPL-1098) is drilled to mate to a variety of mounts or mounting adapter plates, including the TeleVue/Vixen mount adapter (AVT-1011) and TeleVue Gibraltar-5 head.