Black Tropical Blossom High Back Outdoor Chair Cushion Seat dimensions: 20 in. D x 21 in. W x 3.75 in. T. Back dimensions: 24 in. D x 21 in. W x 3.75 in. T. Durable outdoor polyester fabric is UV treated to resist fading for longer lasting vibrant color. 100% polyester filled, a superior poly-fill that helps cushion retain shape over time.