The only difference is that this eyepiece adds a 4th element, a glass achromat type doublet that is placed to increase the focal distance to 15mm. Also being an achromat type doublet, it maintains extremely sharp image quality and maintains perfect color quality. The field of view is 80 degrees and the eye relief is 7mm. As with all my eyepieces there is a provision for light filters. At 900mm focal length this eyepiece produces 43x magnification.
Most seasoned astronomers appreciate what that means.
The lower the magnification the more field of view you have. But this lens goes a step further. When you look through this eyepiece you can barely see the end of the field of view. There is no color distortion. Dense and wide star fields are a pleasure to view.