M42-M48 Spacer - 16.5mm

The threading is smooth and precise—no wobble or cross-threading when I attached it to my corrector. Finally got the exact spacing I needed for my field flattener. This little ring solved my focus issue instantly.

Needed exactly 16.5mm to hit the back focus on my corrected refractor and this hit it dead on. Threads are clean on both the M48 and M42 sides, no cross-threading at all. Stars are round corner to corner now.

Threaded straight onto my field flattener without any cross-threading, and the 16.5mm spacing landed my back focus right where it needed to be. Stars are round to the corners now instead of the elongated blobs I was getting before.