The Press-O-Film X-Coarse Grade (1.5-4.5 mils / 38-115 microns) Replica Tape Roll is used to measure the Testex Tape and determine the average maximum peak-to-valley height of the blasted profile. Measurements are made by firstly zeroing the gauge on 50m (2mils). This is to allow for the film backing. Place the replicated area between the anvils and gently lower the moveable anvil onto the film. The reading can now be taken, giving you the average peak-to-valley height of the blasted profile. Supplied in a Carrying Case with Burnishing Tool. The Testex Snap Gauge is available in a Test Kit, comprising 2 rolls of X coarse Testex (specify if you require other grades), Snap Gauge, Training Surface, Burnishing Tool and instructions.