Step Ring Set 42mm 48mm

(2) Telescope Camera Adapter Step Rings
"T" (42mm) to 48mm AND 48mm to "T" 42mm

Step Up & Down Ring Set
(1)  Male 42mm (0.75) "T Mount" to Female 48mm (0.75)
(1)  Male 48mm (0.75) to Female 42mm (0.75) "T Mount"

For Telescopes and Cameras using "T2" Threads, not "M42" (1.0) Threads

You may have purchased other 42/48mm step rings and found they only thread on a half turn or so. The problem is the thread "pitch". Most common step rings have "M42/M48" threads with a wider thread pitch of 1.0. For many Camera and Telescope tasks you need a "T2" Thread with a finer 0.75 thread pitch.

This set includes both a Step-Down Ring and a Step-Up Ring. The threads on these rings are all 0.75 Pitch. Commonly called "T" or "T2". These are NOT "M42" threads which have a 1.0 pitch.  "T2" Threads are commonly used on Camera T-Rings and Telescope Fittings.