The #ATFB is CNC-machined from solid aluminum for strength and durability, and is anodized a non-reflective matte black. Its lock knob is chrome-plated.

The mounting base’s two-piece design lets it be used in either of two ways. The mounting stalk by itself is 13.5mm wide and will fit into the finder mounting bracket provided with most larger Astro-Tech and TMB refractors and into the Antares quick release finderscope bracket, as well as into most other brands of quick release bracket shoes.

If both pieces of the two-piece base are used, the curved base will mount on small Astro-Tech refractors, the TMB-80 refractor, and most William Optics and Stellarvue refractors (all using the mounting hardware supplied with the base). The underside of the mounting shoe is felt-lined to keep from scratching your telescope’s finish.

The two-piece base can also be used on most catadioptric telescope rear cells (using the existing telescope trim hardware that seals the accessory mounting holes located at the 1 o’clock position on the telescope’s rear cell). The sharper curvature of the base needed to fit smaller refractor bodies may leave a small cosmetic gap between the underside of the base and a larger catadioptric telescope body.