As per your higher temperature, fire & thermal resistance requirements Accurate Rubber Corp mfg & supplies high quality high temp gasket & cable sleeves.
Rubber Gaskets – Fournier Rubber & Supply Co.
Silicone Rubber Gaskets for Sealing and Insulation
Viton Fluoroelastomer Rubber Gasket
Silicone Foam Tape - High Temperature PSA - S600 - Pres-On
Fabbay 2 Pcs Silicone Rubber Sheet Flexible High Temp Gasket
Waterproof sleeve wire cable seal small silicone rubber grommets
High Temperature Silicone Seals - The Rubber Company
High Temperature Edge Trim Silicone Rubber Oven Door Gasket
High temperature heat resistant U type silicone rubber seal strip