Cold Plates - Solid Aluminum - 99.7% Pure Aluminum with 304 Stainless Steel product lines - Tilted and polished top surface to assure maximum cooling performance - Stainless Steel tub ing Fits Opening Size: 17" x 19" No. of Circuits: Six Circuit Leng th: 2 at 27' and 4 at 12' Tube I.D.: 5/16" and 5/