Model 5P9937 Telescope Adapter Ring Key benefits Solves thread mismatch quickly: converts an M48 female thread to an M42 male thread (commonly known as T2 thread), letting you attach cameras, focusers, or optical accessories without modification. Low profile, secure connection: a 7 mm total length with a 4 mm flange distance and 3 mm thread depth keeps the optical train short while maintaining stable, lowplay mounting. Lightweight and durable: precisionmachined from metalaluminum for reliable alignment and longterm use, with a clean black finish to reduce stray reflections. What makes it stand out Precise fit: frame diameter 50.7 mm ±0.1 mm and inner hole diameter 39 mm for consistent tolerances and repeatable installation. Compact design: net weight 5 g keeps added mass minimal for sensitive focuser assemblies and camera mounts. Ready to use: supplied with one adapter ring and one plastic storage box for safe transport and storage. Specifications Model: 5P9937 Application: Telescope Material: MetalAluminum Internal thread: M48*0.75 mm External thread: M42*0.75 mm (commonly known as T2 thread) Thread depth: 3 mm Flange distance: 4 mm Total length: 7 mm Inner hole diameter: 39 mm Frame diameter: 50.7 mm ±0.1 mm Color: Black Net weight: 5 g Gross weight: 16 g Package contents: 1 adapter ring, 1 plastic storage box Typical use scenarios Astrophotography: Attach a DSLR or mirrorless camera with an M42 T2 mount to a telescope with an M48 adapter thread for direct prime focus imaging. Accessory swapping in the field: Quickly adapt focusers, field flatteners, or reducers that use M42 threads to telescopes that provide M48 connections. Visual observing setups: Use to connect eyepiece holders, extension tubes, or other optical components while preserving a short back focus. Practical notes Check thread specifications on your telescope and accessories before installation to confirm compatibility. The precise machining and tight tolerances reduce wobble and help maintain optical alignment during imaging or observing sessions.