Review on Utility Knife, BIBURY Upgraded Version Heavy Duty Box Cutter, Pocket Carpet Knife With 10 Replaceable SK5 Stainless Steel Blades, Belt Clip, Easy Release Button, Quick Change And Safety Lock-Red by Andrew Krishna

In order to open it there is a little nub on the outside of grip where an axis style lock would be. This also functions as the blade change mechanism. In order to close it there is a liner lock. Having two separate locking mechanisms depending on whether its opened or closed makes it fairly fumbley to work with - one of have been sufficient and preferable. The axis screws aren't a standard head so adjusting the open close tension is difficult. From the factory both of the knives i opened were fairly stiff and couldn't easily be opened with one hand and closing with 1 hand was a chore. I wouldn't make the purchase again but they worked for what i used them for. From now on i'll just use the old style carpet knife with the slide out knife - they are similar cost and less annoying to use.