Have you lost the dustcap for the telescope side of your SCT 2" diagonal? Or perhaps like me, you bought a diagonal that didn't have a dust cap.
This is a rubber dustcap that fits tightly, yet will hold firmly in your diagonal. It will fit a diagonal with an inside diameter of 38mm or 1.5". Fits Celestron and Meade SCT diagonals. Will not fit EdgeHD models, or any model with a 3" diagonal.
Keep your diagonal mirror clean and ready to use.