Johns Manville Microlite® B is a lightweight, flexible blanket manufactured using flame-attenuated borosilicate glass fibers and bonded with a thermosetting phenolic resin. The flame-attenuated process used in the manufacture of Microlite B provides uniformly distributed glass fibers with low heat transfer characteristics, excellent acoustic performance and high tensile strength. The resilient glass fibers prevent vibrational settling. Microlite B blankets are designed for applications where temperatures do not exceed 450°F (232°C).