The JMI Telescopes 2" Enhanced Extension Tube adds 2.63" (~67mm) of optical path length to your telescope combination, and is useful for retaining the optical path length when replacing a star diagonal or a prism with a shorter accessory, such as a photo adapter. It may also come in handy when converting to a JMI focuser, which are so low profile that they often move the focus point too far inward. JMI Extension Tubes also reduce minimum focusing distances, allowing closer observations of subjects when focus is moved out by eyepiece projection, use of a Barlow lens, etc.
As the "Enhanced" version of a JMI Extension Tube, this uses a brass compression ring to affix 2" accessories, adding some security and preventing the marring of components which can occur with traditional set screw fixtures. It also accepts 48mm screw-in filters (for 2" eyepieces) upon the bottom of the barrel.