PBI (Polybenzimidazole) is a high performance organic fibre which does not burn in air, retains it's strength and suppleness even when charred, will not melt or emit toxic fumes or vapours, and has excellent flexibility.
The KB series PBI are 22 oz., and have been tested up to 925C. The HB Series PBI are 45 oz., and have been tested up to 1425C. There are several styles available, each with a fully insulated wool line featuring Aramid (a microbial blocker to keep liners fresh).
Note: Covermitts are worn over gloves to provide additional protection, and should not be worn by themselves.