The mesh screen attachment is recommended for people who live in climates with normal to high rainfall and bug issues. The screen will not only act as a barrier for driving rain to enter the box but it will also keep out any insects and critters. The screen is attached via Industrial strength velcro strips (included) and is easily detached. If you purchase this option with the Solarium, the velcro will be attached to the box and the screen. All you have to do it attach the screen.