u003cbr/u003eA prism type is the alignment of the eyepieces and the barrels. There are two types of prism types– the “Porro prims” and “roof prism.” The difference between the two terms is the alignment with the eyepieces.u003cbr/u003eu003cbr/u003ePorro prisms have wide barrels in front that does not align with the eyepieces while the roof prism models have eyepieces and objective lenses aligned.