In the ultrasonic testing of welds, the 6 dB drop technique is commonly used as a way to size the length of discontinuities. However, the technique is often misapplied, which can result in multiple smaller discontinuities remaining after repairs. This is frustrating for both welders and inspectors alike. This webinar reviews how any dB drop technique can result in sizing errors and discusses the proper application of the 6 dB drop technique, as well as its application to common codes such as AWS D1.1 and ASME V.