Thoroughly test the fabric on your aircraft for minimum FAA requirements without removing or punching any holes in fabric. Accurately calibrated in one inch pounds, tester should be pushed directly against the fabric at right angle, evenly and slowly taking note of its reading at all times. Reading is taken at the point where the small tube telescopes into the large tube. For actual fabric strength, it is necessary to apply enough pressure to break the small point through the fabric noting the reading at that time. Store in box away from dust and dirt.