Aluminium Alloy M48*0.75mm Female to M54*0.75mm Male Adapter Ring for Telescope Specification: All metal construction and anodizing aluminum process, durable for long time use High quality anodized aluminum adapter M48 female thread to M54 male thread adapter. Converts an M48x0.75mm male thread to a M54x0.75mm male thread. OR Converts an M54x0.75mm female thread to a M48x0.75mm female thread With it you can convert a female M54x0.75mm thread to a female M48x0.75mm thread with minimum possible mechanical length. External Thread: 5.5mm(M54x0.75mm) InternalThread: 5.5mm(M48x0.75mm) Overall Length: 5.5mm Package Include : 1 x Conversion Ring