Specification Brand : Generic BulletPoint1 : Focusing Problem Elimination: The extension tube has M48 female thread and M48 male thread, which is used to solve the spacing problem in astrophotography and eliminate a series of focusing problems. BulletPoint2 : Eliminate Redundant Light: The design of female thread can eliminate stray light and reflected light, making the image clearer and more perfect. BulletPoint3 : Variable Combination: The required spacing can be achieved by combining several extension rings of different lengths, you can use 1, 2, 3 or 8 extension rings as required. BulletPoint4 : Type: Astronomic telescope M48 threaded extension tube, the height of the extension tube is 3mm, 5mm, 7mm, 10mm, 12mm, 15mm, 20mm and 30mm. BulletPoint5 : Aluminum Alloy Material: All metal structure and anodized aluminum process, , using this extension tube can obtain the correct image scale or the spacing required by the reducer or field flattener. Color : Plastic CompatibleDevices : 2-inch eyepieces CompatibleDevices1 : Camera CompatibleDevices2 : Eyepiece ExternallyAssignedProductIdentifier : 7604960764274 EyePieceLensDescription : Helical Finderscope : Reflex FocusType : Manual Focus ItemName : 8 PCS M48X0.75 Length Extension Tube Kit 3 5 7 10 12 15 20 30mm Extending Ring for Astronomical Telescope Photography ItemPackageDimensions_Height : 6 centimeters ItemPackageDimensions_Length : 16 centimeters ItemPackageDimensions_Width : 10 centimeters ItemPackageQuantity : 1 ItemTypeKeyword : telescope-photo-adapters Manufacturer : Generic Material : ABS ModelName : Genericg4d21yop38 ModelNumber : Genericg4d21yop38 PartNumber : Genericg4d21yop38 PowerSourceType : Solar Powered ProductDescription : 1. Focusing Problem Elimination: The extension tube has M48 female thread and M48 male thread, which is used to solve the spacing problem in astrophotography and eliminate a series of focusing problems. 2. Eliminate Redundant Light: The design of female thread can eliminate stray light and reflected light, making the image clearer and more perfect. 3. Variable Combination: The required spacing can be achieved by combining several extension rings of different lengths, you can use 1, 2, 3 or 8 extension rings as required. 4. Type: Astronomic telescope M48 threaded extension tube, the height of the extension tube is 3mm, 5mm, 7mm, 10mm, 12mm, 15mm, 20mm and 30mm. 5. Aluminum Alloy Material: All metal structure and anodized aluminum process, , using this extension tube can obtain the correct image scale or the spacing required by the reducer or field flattener.