Dove prisms have an unusual and very interesting characteristic , if you look through the prism and rotate it around a longitudinal axis, the image rotates through twice the angle through which the dove prism itself rotates. For optimal peformance, use dove prisms with collimated light.

Description Of Dove Prism

Ecoptik dove prism have an unusual and very interesting characteristic, if you look through the prism and rotate it around a longitudinal axis, the image rotates through twice the angle through which the dove prism itself rotates.