Imagine without a screw, how can we fasten or secure an object against another object, or to untied an object? I can't think of anything besides screw driver, ball screws, and any screws to do that. The other day my husband trying to fix our ceiling lights outside the house but we couldn't open that thing because we don't have the right screw for it. It is so annoying to think about that we have to depend on that small little thing. Such a life. In this modern age? Forget it! Good thing though I can call our maintenance office to do the work for us.