Mayne 4829-B Nantucket Polyethylene Window Box, 2', Black This window box features a double wall design creating a water reservoir. Mayne melded polyethylene planters are made from 100% high-grade polyethylene Includes 2 Steel wall mount brackets with a Black powder coated finish Outside dimensions: 24"L x 11.5"W x 10"H. Inside dimensions: 20"L x 8"W x 7.5"D, holds approx. 2.5 gallons of soil. Water reservoir capacity is approximately 1.6 gallons (6 litters)& The weather-proof and ultra-tough construction allows you to enjoy your window box all Year long with very little winter preparation 15 Year Warranty - residential application, 5 Year Warranty - commercial application made in the USA