<p>This is an excellent 1.25-inch double-threaded focuser with a 10mm adjustment stroke. It is light and compact, made of all metal, and .</p> <p>During the focusing process, the inserted CDD eyepiece or mirror remains non-rotating and only makes linear movements, which is conducive to observation and astronomical photography.</p> <p>The meticulous craftsmanship makes its micro-focusing extremely precise, and it is still smooth and stable even at huge magnifications.</p> <p>1. -new double-helix focuser</p> <p>2. High-precision double-helix focuser for guide mirror\/finder interface</p> <p>3. Solution to slow focusing of telescopes or telephoto lenses</p> <p>4. Made of all metal, </p> <p>Inner diameter 1.25inch</p> <p>Stroke 10mm</p> <p>Adjustment accuracy 0.05mm</p> <p>Top external thread M42x0.75</p> <p>Bottom interface 2 inches (50.8mm)</p> <p>Bottom inner ring external thread M31x0.5</p> <p>Minimum height 46mm</p> <p>Maximum height 56mm</p> <p>Colour:Black</p> <p>Material:Metal</p> <p>Package Contents:</p> <p>1 x Double Helical Focuser</p> <p>Only the above package content, other products are not included.</p> <p>Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +\/- 1-3cm.</p>