W&W Astro flexible dew shield prevents dew appearance on the lens. It’s made to be easy fit on your telescope tube. It has similar length to telescope’s outside circumference and should be placed at the front end of the tube. Inside of the shield is covered with black felt fabric to improve contrast.
Additionally shield has built in 12V heater strap to provide more dew protection. The heater is low powered so can be powered without controller.