Watch the video and let Dr. Andreas Hardock, Application Marketing Manager for ESD and EMC at Nexperia show you why in snap-back devices the clamping voltage can be lower than the break down voltage and why a low clamping voltage is key in protecting your circuitry. 

More information on snap-back behavior watch the previous video: What is the difference between Zener and snap-back behavior? - Nexperia shorts https://youtu.be/m8gyKH1LIMs