Bob's Knobs for Celestron SCT 5” f/6: Precision Tuning for Rare Models Exclusively for Celestron SCT 5" f/6: Designed specifically for the uncommon Celestron 5” (13 cm) f/6 SCT, not suitable for the more common 5” f/10 SCT models. Part Details - Part: C5f6: Telescope Suitability: Perfectly fits the rare Celestron 5" f/6 SCT. Knob Features: Made of black plastic, each knob is 13 mm (1/2”) in diameter, facilitating effortless and accurate adjustments. Thread Quality: Constructed with black anodized aluminum alloy threads for a secure and durable connection. Model Identification: Rare Model Fit: These knobs are tailored exclusively for the C5 f/6 telescope model. Verify your model type to ensure compatibility. Compatibility with Factory Dust Cover: Dust Cover Fit: Ensures that the factory dust cover remains functional and fits as normal with Bob's Knobs installed. Enhanced Telescope Maintenance: Ideal for owners of the rare Celestron SCT 5” f/6 telescope seeking an easy, tool-free solution for precise collimation adjustments.