Designed for attaching a Canon DSLR camera to any of the Sky-Watcher 0.85x Focal Reducer/Correctors.
M48 rings are used for larger format imaging. These are different than the standard T-Thread. M48 rings are to be used on the Esprit and ProED series when using the dedicated field correctors.
NOTE: this is a specialized adapter for Sky-Watcher focal reducer/correctors. It uses a 48mm ring, while the standard t-ring uses a 42mm ring. This M48 adapter will not connect to standard t-adapters.