Specialty tapes and films use proprietary or patented technologies and constructions, and are designed for specific industries and specialized applications. Product specifications include dimensional parameters such as width, length and thickness, as well as various thermal and electrical properties. Thermal properties for specialty tapes and films include temperature resistance, thermal conductivity and coefficient of thermal expansion (CTE). Electrical properties for specialty tapes and films include electrical resistivity, dielectric strength, dielectric constant or relative permittivity, dissipation factor, and test frequency range. Test frequency is an especially important consideration in selecting materials for radio frequency (RF) and microwave applications. Dielectric constant, dissipation factor, or loss factors may change with the operating frequency.