This feeder holds a standard 4 lb. salt or mineral block. Raised ribs and drainage holes keep blocks dry. Contoured mounting plate has holes to allow for permanent mounting (hardware not included). Made of tough, impact resistant, high-density polyethylene which protects against warpage, stress cracks, and UV damage. Measures 9.31" long by 6.06" wide by 5.56" high, holds one 4 lb. salt block or 1 quart dry material (will not hold water).