(Quantity One) 28W x 15H x 4Thick. The dimensions are 4 “ at the top of the back rest. 6” At the bottom. The 45 degree angle is 5.5” at the top and 8” at the bottom. 28” X 15” x 4”. At the top back. 24” x 15 x 4” at the top front. 28” x 15” x 6” at the back bottom. 24” x 15” x 6” at the front bottom.