Orion 5124 2-Inch Telescope Eyepiece Extension Tube Extension tube provides extra focuser "back travel" often needed for short-range terrestrial viewing through a telescope, or for astrophotographic applications Adds 2" of extension, fits in 2" telescope focusers, and accepts 2" eyepieces or accessories Features two locking thumbscrews to secure any inserted astronomy accessory Threaded for use with 2" Orion eyepiece and astrophotography filters Machined and anodized aluminum tube