Humidifier Pad Compatible Grainger Part Number 31TP26 31TP27 Compatible Manufacturer Model Number 110 220 500 500A 500M 550 550A 558 Overall Depth 1 3/4 in Overall Height 10 in Overall Width 1 3/4 in Overall Length 9 3/4 in Coating Ceramic Includes Water Panel Pack Quantity 1 Product Type Water Panel Evaporator