Starlight Instruments Dust cap w/ desiccant for any 2.0" openingA must have item that you never want to use (because it means you put your scope away).... The DDC-2 (2"Desiccant Dust Cap) was designed by Starlight Instruments, LLC to help you protect your telescope from harmful moisture, and dust particles while in strorage. Includes self indicating desiccant starter pack. The packs turn from blue (when good) to pink (when bad), and are available through Starlight Instruments, LLC.