The Saunum External Salt Tray is positioned within the air stream of the heater so that salt ions are propelled throughout the sauna room to deliver health benefits more effectively. For use with Air Perfect Series Sauna Heaters. Model AIR PERFECT EXTERNAL SALT TRAY Construction Material Stainless Steel Width 10" (25.4 cm) Depth 3.5" (8.9 cm) Height 1" (2.5 cm) Weight .55 lbs