A Spring-Assisted or Assisted-Opening Knife opens when you push on the thumb stud and the internal spring opens the knife the rest of the way. Assisted-Opening, or AO knives are sometimes consufed with switchblade knifes.

The difference between a switchblade and an AO knife is that the switchbalde can open from just pushing a button. The Assisted-Opening knife requires you to push the thumb stud to get it started.

Stiletto Style Assisted Opening Knives

Assisted Opening Knife A Spring-Assisted or A...

Trench Extreme Folder with Knuckles

Kriss Blade Stiletto Style Knives

Assisted Opening Knife A Spring-Assisted or A...

13" Giant Stiletto Style Knives

Etched Handle Assisted Opening Knives

Extreme Ops Combat Ready Knives

8" Black Joker OTF Style Folding Knife W/Clip

The Joker Jr looks like the popular OTF, but i...