CoorsTek 65582 High-Alumina Rectangular Tray, 750mL Capacity, 188mm Length, 140mm Width, 42mm Height Highly chemical-resistant Recommended for use with refractory metals such as molybdenum, platinum, rhodium, tungsten, tantalum and iridium Suitable for glass melting, including borosilicate glass Permeability: Gas-tight. Water Absorption: None