This lid has a unique ventilation system for healthy plants. It is part of the growhouse set of lid, tray and saucer. Together it is a grow house that allows you to propogate seeds, to grow your own vegetables and flowers or use it to germinate micro greens and cut straight from the growhouse. Made with 100% recycled materials. Manufactured using 100% Wind Energy with our own windmill. Designed and made in Holland.