New, lower profile! The Baader Focusing Ring Collar # T2-30 # 1905131 slips onto your 1.25” eyepiece barrel and enables you to adjust and lock a reference stop for repeatable eyepiece focus. This allows you to set an eyepiece to be precisely parfocal with another eyepiece or piece of equipment (for e.g., setting an eyepiece parfocal with a CCD camera for visual framing and focus). Multiple collars can also be useful in pre-setting Bino-Viewer eyepieces for repeatable focus (to compensate for eye-to-eye focus differences).
The focusing collar is 0.23" (6mm) thick, and incorporates two nickel plated brass lock screws, which are spherical-tipped to minimize eyepiece barrel damage. Weight = 0.5oz.