The screw-less focuser for the telescopes -simply slides in Many telescopes have a focuser which does not allow very precise focusing. Especially difficult jobs such as focusing on a planet can be a real challenge. This helical focuser elegantly overcomes the problem. It is suitable for both refractors and Newtonian telescopes, but is also particularly useful with Schmidt-Cassegrain telescopes. You need to do nothing more than to connect it to your existing focuser. Primary mirror interfaces & Interface The one side of helical micro focuser is M48X0.75 male thread suitable for M48 thread for your camera, the other is M48X0.75 female thread, it also has a 2" barrel suitable for 2" focusers. Main Feature: Accuracy： 0.1mm Interface: 2" with M48*0.75 male thread Primary mirror interfaces:M48X0.75 Focusing stroke: 39mm Minimum length: 88mm Longest length: 127mm Color: black Be made by full metal Help To precisely Focus Many telescopes have a focuser which does not allow very precise focusing. Especially difficult jobs such as focusing on a planet can be a real challenge. This helical focuser elegantly overcomes the problem. You need to do nothing more than to connect it to your existing focuser. Suitable for all 2" focusers/M48 thread for your camera The helical focuser has a 2" barrel. This allows it be inserted into the focuser just like an eyepiece. Its separate focusing mechanism now takes over the job of precision focusing. The accessory side of the focuser has a M48 thread for connecting your camera. The Focuser has A Fixed Orientation A further advantage is that the accessories, like a camera, do not rotate with the focuser. Therefore the orientation of the image remains unchanged. Via the optional M48x0.75 female to M42x0.75 male thread telescope adapter ( Asin: B01DIRJ72I ), the focuser can be easily attached to a CCD camera or DSLR camera with T-ring adapter, so the connection to your camera becomes child's play. Sharper focused planets via the helical mechanism Once the helical focuser is attached, simply turn the oversized focusing knob - which you can control easily even with gloves on in winter. The rotating mechanism allows very smooth and continuous focusing, and without any play. Your new focuser does exactly what you tell it to. Adjustment Accuracy: 0.1mm The accuracy can reach 0.1mm, 39mm focusing stroke, and more precise focusing. Will meet your need for precise focusing during photography, lightweight and portable, it's more convenient to carry and use. Thread For Eliminating Light Effectively reduce stray light interference, not only improve the brightness of the image, but also effectively reduce the dark edges formed, the edge details of the image are clearer.