Keep out stray and unwanted light from your 20" Truss Tube Dobsonian telescope with a lightweight light shroud. Keeping the path dark between your secondary and primary mirror will boost image contrast and brightness bringing out more details. Constructed of opaque black nylon with excellent stretch, each end of our DOB light shroud has an elastic band to keep the shroud in place and allow for an easy fit and installation. Breathable nylon will let air circulate and yet keep dust away, keeping your optics clear and avoiding any unnecessary pressure from the breeze. A must-have for the suburban observer where stray light interferes.