FOSTER C.I. MASTIC is a tough, durable, high solids vapor barrier asphalt cutback mastic. Because of its low vapor permeance, it is an ideal surface coating for low temperature insulation on outdoor applications. C.I. MASTIC may be used on heated lines, vessels, and equipment in intermittent or dual temperature service to prevent the entrance of water vapor into the insulation during off periods or on cold cycles. C.I. MASTIC may be used as a solvent based adhesive for asphaltic felt vapor barrier jackets on pipe and duct insulation. C.I. MASTIC meets the requirements for water proofing mastics in the TRI-SERVICE SPECIFICATION for UNDERGROUND HEAT DISTRIBUTION CONDUIT SYSTEMS.