The Geo Double Prism Optical Square comprises two pentaprisms of quality optical glass, housed in a sturdy aluminium casing. The housing cover can be rotated to cover the viewing window and protect the prisms when not in use. The prisms are mounted above and below the ‘through’ sighting window, the upper one sighting from the right side, the lower one from the left. The pentaprisms are ground to refract the views by exactly 90°.
Easy to use, simply hold the handle then sight through the yellow lens in the middle to align to a target, then through the clear prisms above and below you can see at right angles to your left and to your right. To get even more accurate there is a slotted hollow handle for attaching a plumbob cord. The extra wide viewing window makes targeting easy. Protective metal cover rotates to expose or protect the prism.
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