3M Electrical moisture block EMB is a self-fusing, rubber based insulating adhesive/sealant designed to prevent the migration of water along harness wiring. EMB block is supplied on a release liner and offered in three standard sizes to accommodate different size wire bundles. - EMB block is compatible with typical wire insulation such as PVC, synthetic rubber and cross linked polyethylene. Specially formulated rubber adhesive/sealant for moisture proofing wire bundles.