Bob's Knobs for Astro-Tech Newtonian Secondary: Precision and Ease Customized for Astro-Tech Series: Specifically designed knobs for the Astro-Tech Imaging Newtonian (IN) and Dobsonian (D) series secondary mirrors. Wide Range of Compatibility: Suitable for Astro-Tech AT6IN, AT8IN, AT10IN, and AT12IN imaging Newtonian telescopes. Product Details - Part: CNsec35: Telescope Fit: Perfectly matches Astro-Tech AT6IN, AT8IN, AT10IN, and AT12IN models. Knob Design: Made of black plastic, each knob is 13 mm (1/2”) in diameter, designed for easy gripping and adjustment. Durable Materials: Features threads made of stainless steel for longevity and reliable performance. Complete Set Pricing: Offered as a complete set of knobs at a single price, providing value and convenience. Easy Installation and Adjustment: Designed for simple installation and user-friendly adjustment of the secondary mirror. Enhance Telescope Functionality: Ideal for astronomers seeking to improve the usability and maintenance of their Astro-Tech telescopes.