This pack of 10 1.25" caps allows you to protect your 1.25" eyepieces. They fit on the barrel end (base) of the eyepiece that you insert into the focuser. They are made of soft yellow plastic so they are quick to put on and take off, and easy to see in the dark. They also fit over the top ('eye end') of Celestron/Vixen silver top Plossl eyepieces. For caps to fit the top of other 1.25" eyepieces, please see the other items in this store. Because they are made of soft plastic the eyepiece cannot be stood on end.