Compact allmetal adapter and extension tube for reliable telescope and astrophotography use. Key benefits Secure, durable construction: Made from quality aluminum alloy with full metal construction and anodizing aluminium process for longlasting use and corrosion resistance. Accurate optical spacing: Use the extension tube to obtain the correct image focal length or the exact spacing required in astrophotography, solving common backfocus and spacing issues. Compatible with common accessories: Supports M48x0.75 thread to accept 2 inch telescope eyepieces and astrophotography filters, enabling straightforward integration into existing setups. Stable, slip attachment: Side clamping screw with brass locking wing screw prevents accidental slippage and keeps the telescope and accessories secure during use. Improved image quality: Glossy black anodized finish outside; painted flat black and grooved inside to minimize stray light and maximize contrast. Portable and practical: Lightweight, small size, and easy to carry for field work or travel. Features and specifications Material: Aluminum alloy, all metal construction Surface treatment: Anodizing aluminium process; black anodic oxidation treatment to reduce reflections Thread: M48x0.75 Accepts: 2 inch telescope eyepieces and astrophotography filters Mounting security: Side clamping screw with brass locking wing screw Interior finish: Painted flat black and grooved for contrast Exterior finish: Glossy black anodized Practical use scenarios Finetuning back focus for astrophotography: Add the extension tube between your eyepiece, filter, or camera adapter to reach the precise spacing required for sharp focus on deepsky targets. Switching between visual and imaging setups in the field: Quickly attach a 2' eyepiece or an M48 filter and lock it securely with the brass wing screw for stable observing or imaging sessions. Preventing internal reflections during long exposures: The grooved, flatblack interior and anodized exterior help reduce stray light and improve contrast when capturing faint objects. What it solves Eliminates uncertain spacing that causes focus errors or vignetting in astrophotography. Prevents slipping or rotation of eyepieces and filters during use. Reduces unwanted reflections and internal light scatter that degrade image contrast. Compatibility checklist Thread: M48x0.75 Fits: 2 inch telescope eyepieces and M48 astrophotography filters Reliable, purposebuilt accessory for users who need precise spacing, secure mounting, and improved contrast in both visual observing and astrophotography.