The Viagrow 6" heavy duty wide lip mesh pot bucket lid is designed to fit on standard 3.5 and 5 gallon buckets. The 6" net cup bucket lids are great for all hydroponic applications as the mesh pot creates ample aeration for root development. In addition, the black opaque plastic will keep light out thus preventing algae from growing in your growing chamber. For ideal results use VS50 or VS10 Viastone grow rocks as your media in hydroponic applications.