This 2" cap allows you to protect you 2" eyepieces. It fits on the barrel end of the eyepiece that you insert into the focuser. It is made of soft yellow plastic so it is quick to put on and take off, and easy to see in the dark. Fits all brands of eyepieces such as Televue, Takahashi, Meade, Orion, Vixen etc. Because it is made of soft plastic the eyepiece cannot be stood on end.