Finderscope / Finder Scope Starpointer for Astronomical Telescopes - Dovetail Base Type Simple, affordable, and effective red dot sighting device makes aiming your telescope a cinch! It is very easy to adjust. Thumbwheels allow positioning of the red dot horizontally and vertically for precise telescope alignment An adjustable small red LED dot is projected onto a non-magnifying viewing window so you can aim the main telescope quickly and easily The dovetail base fits Celestron, Orion, Skywatcher, Vixen and other silimar dovetails on the telescope. The main part is made of plastic material. But this product works well