The Defiance Dual Action Automatic knife, Pro-Tech’s newest auto knife, is incredible. The knife is a dual action (D/A) which means that you can open it just like a manual open knife–by pulling on the blade to open it up–or you can push the hidden activation button and open it automatically. Most dual action knives suffer from one of two problems. Either the activation button seems unreliable or they seem to suffer from “not so hidden” syndrome. What I mean is, the basic point of a dual action knife is to have a knife that is automatic but that also is not obviously an auto knife. On many dual action knives, the “hidden” activation trigger is really obvious. Not so on the Defiance by Pro-Tech. They very cleverly hid the auto trigger under the very top edge of the G-10 inlay on the handle. The G-10 will depress slightly when pushed and this triggers the blade. The only other dual action knife I have ever seen that even comes close is the “Whiskers” knife, also by Pro-Tech. The “Whiskers” knife had a completely different style of hidden activation (it is activated with a sliding scale) but it also works extremely well. I like the Defiance even better. This is by far, and I mean by several miles, the best Dual Action automatic knife I have ever used.