This 1 1/4", 90 degree erecting prism is the same as used on our top rated Stellarvue finder scopes. This is a correct image erecting prism. The helical focuser has a rubber grip and provides about .6" of travel. Many purchase these to be able to do fine focusing adjustments on telescopes that suffer from image shift when also needing an image that is right side up and correctly oriented.
The erecting prism is fully multi-coated providing extremely high light transmission (greater than 99%). Compared to prisms using Mgfl2 coatings, the contrast is much higher and the stars appear brighter.
Side plates are carbon fiber. The insert tube is threaded for filters. Plastic dust caps are provided.