The Alpine Astronomical Baader 2" Standard Eyepiece Holder with Extension combines three components into a single useful unit. The first piece is a standard 2" eyepiece holder that is outfitted with two thumbscrews and a bronze compression ring to hold your eyepiece without marking or marring it. The second part is a standard 2" nosepiece that has threads on both sides to install eyepiece filters. Using the front filter threads allows you to quickly and easily change filters, and by using the rear threads you can permanently install filters without adding optical length to the system. A step-up ring is used to enable the nosepiece to thread onto the holder. The entire system adds 60mm of optical length, which can be used to achieve the proper back focus for eyepiece projection or afocal photography techniques.