Feature:1. 15mm Length M6 Screw: Each of the 3 lock screws comes with a protective cap to prevent scratching during fixation. They can avoid unaesthetic scratches and pressure marks on the telescope while still ensuring reliable clamping.2. Flat Surface Design: The junction of the guiding scope ring and the base is flat (non curved) to avoid shaking after connecting to the base, ensuring stable connection.3. Width Widening: The guiding scope ring width is increased by 14mm, providing large and sturdy contacting. The 90mm guiding scope ring hole diameter supports 7090mm astronomical telescope diameters.4. Thickened Ring: Aluminum alloy design, sturdy, with a long service life. M6 screws come with scratch resistant rubber caps, reducing the likelihood of leaving traces after scratching.5. Compact and Portable: Easy to carry and can be put into a backpack or pocket. Just take it out and install it when you use it. Its convenience and portability make it an ideal accessory for astronomical observations.Specification:Item Type: Guiding Scope RingMaterial: Aluminum AlloyAperture Support Range: 70-90mmInner Diameter: Approx. 90mm / 3.54inOuter Diameter: Approx. 99mm / 3.90inFrame Width: Approx. 14mm / 0.55inColor: Red.Package List:1 x Guiding Scope Ring3 x M6 Screws1 x 1/4 Inch Screw