This document specifies the characteristics of probes used for non-destructive air-coupled ultrasonic testing with centre frequencies above 20 kHz, with focusing or without focusing means. This document refers to probes based on the piezoelectric effect. Air-coupled probes based on other physical principles may be characterized according to this guideline if it is judged as appropriate. This document excludes periodic tests for probes. If parameters specified in this document are to be verified during the probe’s lifetime, as agreed upon by the contracting parties, the procedures of verification for these parameters can be selected from those given in this document.