(4) Bracket Assembly. The bracket assembly provides a seat for the gunner's quadrant and consists of a level
bar pinned to a bracket. A screw and spring are used to adjust the level bar and then removed after pinning.
(5) Cover Assembly. The cover assembly is a boxlike cover that fits over the elevation counter and correction
counter. It contains windows for both counters and an overlay assembly containing LEDs for illuminating the counter dials.
(6) Extension light. The extension light is used to light the reticle of the M115 panoramic telescope.
d. M139 Elbow Telescope.
(1) Eyepiece Assembly. The eyepiece assembly consists of a cell, eye lens, spacers, field lens, and ring.
(2) Instrument Light Adapter. The instrument light adapter has a dovetail slot for the M36 instrument light lamp
bracket and is positioned over the window in the M139 elbow telescope.
(3) Optical Instrument Prism. The optical instrument prism bends the light 90 degrees. It erects the image.
(4) Objective Cell Assembly. The objective cell assembly consists of a cell, reticle, and ring.