Benchmade Griptillian, thumb hole in blade for opening. I actually hold the lock studs back, and then flip it open for speed. I have carried one for years now, and have always been satisfied. It sharpens up easy enough, and has been used for gutting hogs, deer, snakes, etc., in addition to cutting lots of rope, cord, boxes, tape, plastic sheet, you name it. I have several, and a few of the mini version. Never had any problems.