The 11 inch plant saucer is 30cm in diameter and 25cm (9.5 inches) in diameter at the bottom. All Pots & Planters smaller than 9.5 inches can use the Plant Saucer. Our 3 gallon pot and 5 gallon Pot can also be matched with this bottom plate. Plant Saucer is produced with PP recycled material, which is strong and durable and can be used for 5 to 10 years indoors and 3 to 5 years outdoors.Classic black works well with Cement Planter, Plastic Planter, Glazed Planter,plant planter.