What's new in the model "Universal Zoom Mark IV"? Even Bestsellers can be improved: The fourth generation of this eyepiece weighs 290 g (10.2oz). It now has 55 mm diameter to become useful in dual mode from 55 mm interpupillary distance. Both features make it especially desirable for use with binoviewers. The adjustable eyecup can be removed to expose the M43 video/photo thread and create the maximum "nose space" for using it on binocular viewers. The click-stop action has been smoothed out to more easily access the magnification stops at 8/12/16/20 and 24mm (click-stops are mandatory to easily and precisely set both eyepieces to the same focal length for effortless binocular observation without eye-strain). The zooming-mechanism as well as the inner zooming rails for all lens groups have been modified to improve cold temperature operation and the parfocalty for each focal length has been fine tuned. Most important however - the Mark IV offers almost 4 mm more backfocus. This is most beneficial for applications with a multitude of spotting scopes. Two different Adapters for telescope and spotting scope adaptation are included with the eyepiece. The Mark IV comes with both the 2" and 1¼" nosepieces mounted, each nosepiece having it´s own dust cap and both nosepieces are threaded to accept either 1¼" or 2" eyepiece filters. The Mark IV offers an M43 photo/video thread on top of the eyepiece, to allow attachment of any desired DSLR or T-2 accessory for mounting a video-camera by means of the optional M43/T-2 adapter ring #2958080. Unchanged is the optical quality, 68° field of view at highest magnification (48° at the lowest), Phantom Group multicoatings, a large adjustable eyecup or alternatively two M43 rubber eyecups for bino viewing. The Mark IV likewise accepts adaptation of the 2.25x Hyperion-Barlow onto the 1¼" nosepiece, to transform into a high power zoom, featuring the magnification range of 3.6 to 10.7 mm.