Frequency of recalibration should be based on the critical nature of those ESD sensitive items handled and the risk of failure for the ESD protective equipment and materials. In general, EMIT recommends that calibration be performed annually. Use the EMIT 50424 Limit Comparator to perform periodic testing (once every 6-12 months) of the EMIT SmartLog V4™, SmartLog V5™ and Dual Independent Testers. It may also be used to verify the calibration of the Desco and Vermason Combo Tester X3. The Limit Comparator can be used on the shop floor within a few minutes virtually eliminating downtime, verifying that the tester is operating within tolerances.