Testex Press-O- Film Tape consists of foam with a non-compressible backing. The foam side is rubbed into the surface providing a permanent mold of the profile. The Elcometer 124 Thickness Gauge is then used to measure the peak-to- valley height, 50 tests per roll. Tape profiles; X-Coarse 2.5-4.5 mils and Coarse 0.8-1.5 mils. For other tape profiles, call for details.