From the ManufacturerFor the best performance from our 16" XX16 Truss Tube Dobsonian, this custom designed Light Shroud for the SkyQuest XX16 is a must. It's made of a stretchy nylon blend material that fits like a glove over the truss poles of the XX16, fastening with thick elastic bands on both ends. The water-resistant, opaque black fabric blocks stray light from entering the optical path, thus improving image contrast. It's also breathable, which minimizes unwanted vibration of the scope in breezy conditions. Use of the shroud will lessen the accumulation of dust and dirt on the mirrors during use, and will help prevent dew from forming on them. Made in the U.S.A. WARNING! When using a truss tube Dobsonian for solar observing, always use a Light Shroud and a properly sized solar filter. Make sure there are no gaps between the Shroud and the telescope where direct sunlight can reach the mirror, otherwise eye injury or damage to the telescope can occur. Before using any telescope for solar observing, install protective covers on all optical components. Glancing through an uncovered optical system can cause permanent eye damage. Always install protective caps on all optical instruments if left out during daylight hours.