This is the original prism for the F3. It is smaller than the the HP model AND has a bigger view. Why would anyone want an HP? The HP is a longer eye relief, so you can see the whole frame with glasses on. If you do not wear glasses then this is the one that you want.
This one has a few condition issues. There is a fairly big dent on the top of the prism (see photos) that is causing the windows for the aperture and shutter speed readout to be slightly crooked. The prism still works perfectly however, the windows are not obscured and the glass is clean and scratch free.
Get a deal on a nice prism!