1. Adopt coaxial fastening, the inner ring is made of PETF material, which can be quickly and synchronously locked without damaging the eyepiece and other accessories.
3. Allows the use of M42 eyepieces with telescopes that normally require 1.25inch eyepieces
2. Handy hybrid adapter allows you to use older M42 eyepieces in modern telescopes that normally only accept 1.25Inch eyepieces.