Bob's Knobs for Celestron StarHopper 12" Primary: Enhanced Support with Strong Springs Optimized for Celestron StarHopper 12" f/5: Designed specifically for the Celestron StarHopper 12” (30 cm) f/5 Newtonian telescopes. Part Information - Part: CNspr: Telescope Compatibility: Perfectly fits the Celestron StarHopper 12" f/5 Newtonian models. Enhanced Mirror Support: The replacement stainless steel springs are stronger than factory-supplied springs, providing robust support to maintain primary mirror collimation. Advantages of Upgraded Springs: Prevents Sagging: These springs counteract sagging caused by the weight of the mirror cell, ensuring consistent and reliable collimation. Recommended Use with Locking Screws: For optimal control and stability, it is advised to keep the mirror locking screws in place. Improved Telescope Performance: Ideal for astronomers using the Celestron StarHopper 12" who seek to enhance their telescope's collimation stability and overall observational quality.