Features: Made of high quality material, which is anti-rust, wear-resistant and durable. It has an internal brass ring that the set screw hits to hold your 2 inch eyepiece inside. Large thumbscrew, easy to install the adapter on telescope. Good accessory for astronomy telescope. Fit for Schmidt Cassegrain. Specifications: Material: Aluminum Alloy Color: Black Fitment: for Schmidt Cassegrain Telescope Mount: 2 inch SCT type Inner Diameter: 5.2cm/2inch Outer Diameter: 5.9cm/2.3inch Package Included: 1 x Adapter Package List 1Made of high quality material, which is anti-rust, wear-resistant and durable. 2It has an internal brass ring that the set screw hits to hold your 2 inch eyepiece inside. 3Large thumbscrew, easy to install the adapter on telescope. 4Good accessory for astronomy telescope. 5Fit for Schmidt Cassegrain.