LW Scientific Focusable C-mount Trinoc Pipe w/0.5x Lens for Better FOV. 5X reduction feature have been optimized for the i4 Trinocular head. This feature takes the already large field of view of the Trinococular head and makes it even more manageable. The low-back comfort-grip focusable pipe lens eliminates the need for focusing knobs on the nosepiece and eyepieces. This feature improves the stability of the system by getting rid of the unnatural kinking that usually occurs when a compression ring is present on the end of the pipe. Another benefit of this focusable c-mount is that it allows you to use clip-on diopters to insure that the exit pupil is a constant size and that there are no surprises in the field. Unlike a zoom lens this will not distort the original field-of-view and there is no "phase" effect that would shift the field from what it was when the instrument was assembled. What's more this focusable c-mount will continue to work even if the nosepieces are removed. This is because the position of the c-mount is optimized for the i4 trinocular head. There is no optical interference between the objective and the eyepieces so the diopter setting will not change unless the eyepieces are moved closer or farther away from the optical axis. Features of LW Scientific Focusable C-mount Trinoc Pipe w/0.5x Lens for Better FOV: Focusable c-mount for i4 Trinocular Microscope 0.5X reduction for better field-of-view Package Contents: LW Scientific Focusable C-mount Trinoc Pipe w/0.5x Lens for Better FOV LW Scientific I4P-CMNT-F05X: Focusable C-mount Trinoc Pipe w/0.5x Lens for Better FOV