TapeCase Aluminum Alloy Foil Tape-Converted from 3M 3311, is a 3.6 mil industrial grade masking tape suitable for sealing aluminum faced seams and joints as well as fulfilling several general repair and maintenance applications. The backing of this product is constructed from a very conformable metal foil perfect for adhering on uneven or irregular surfaces. This tape is designed for all weather performance and capably resists water vapor, odor and smoke transmission.