Bob's Knobs for Astro-Tech AT10RC Secondary: Enhanced Telescope Adjustability Designed for Diverse Brands: Ideal for Astro-Tech, GSO, iOptron, MallinCam, Orion (US), and TPO 10" f/8 Ritchey-Crétien (RCT) secondary mirrors, both solid and truss-tube models. Part Information - Part: AT10RC: Telescope Compatibility: Perfectly fits the secondary of 10" f/8 RCT telescopes from a range of brands. Knob Specifications: Crafted from black plastic with a diameter of 16 mm (5/8”), ensuring easy grip and precise adjustments. Thread Quality: Features durable stainless steel threads for long-lasting use and stability. Practical Design Considerations: Dust Cover Compatibility: While the factory dust cover may contact the knobs, it will still stay in place, ensuring protection. Alternative Cover Option: For those who prefer, a shower cap can serve as an effective substitute dust cover. Easy Installation and Use: Designed for straightforward installation, providing a user-friendly solution for secondary mirror adjustments. Optimize Telescope Performance: An essential accessory for astronomers looking to enhance the functionality and maintenance of their 10" f/8 RCT telescopes.