3mm長 48mm 間隔環 (SFE-M48-003)

I needed exactly 3mm more back focus to get my stars sharp across the frame, and this ring threaded on perfectly without any binding. The CNC machining is precise and the anodized finish matches my other gear.

The machining is clean and the ring sits perfectly flat, which is what you want when you’re chasing that last millimeter of spacing. It did exactly what it was supposed to for my setup, though I wish it came in a set of different thicknesses to tweak faster.

Finally got my back focus exactly right with this 3mm spacer—the threads are perfectly smooth and it seated flush against the flattener without any wobble.