Fully metal construction and anodized aluminum process, durable for long-term use. Use this extension tube to achieve the correct image scale or precise spacing required for reducers or field flatteners. The extension tube features a T2 internal thread and a T2 external thread, helping to solve spacing issues in astrophotography and eliminate various focusing problems. Type: Astronomical T2 Thread Extension Tube Male thread: M42*0.75mm Female thread: M42*0.75mm Connects or extends the tube length for M42*0.75mm products Color: Black Length: 5mm, 10mm, 15mm, 20mm Please Note: These items have M42 (42mm) thread diameter, not M48 thread diameter Due to different production batches, the surface finish (matte black or shiny black) is shipped randomly. Note: Please allow 0–2mm error due to manual measurement. Ensure you are comfortable with this before purchasing. Due to variations in monitor displays, the image may not reflect the actual color of the item. Thank you. If you are highly sensitive to these details, please do not purchase. Package Includes: 1 x Extension Tube Kit (size can be selected)