Material Furnace / Boiler Door insulation & sealCoke Oven door jam sealExpansion Joint packingHigh Temperature Gasketing & PackingMaintenance in Foundaries, Refineries, Power Plants & Steel Plants Type Pilot Brand Ceramic Mattress are 25mm (1inch) refractory fibre needled mat made without binder from Pilot Ceramic Yarn fibres. They have excellent resistance to most chemicals and their thermal, physical properties are restored upon drying.