Mayne 4830-G Polyethylene Window Box, Green This window box features a double wall design creating a water reservoir. Mayne melded polyethylene planters are made from 100% high-grade polyethylene Includes 3 Steel wall mount brackets with a Black powder coated finish Outside Dimensions: 36"L x 10"W x 11.5"H. Inside Dimensions: 31.5"L x 8"W x 7.5"DWater reservoir capacity is approximately 2.5 gallons (9 Litters), holds approx. 3.5 gallons of soil 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