When you buy a hex key (Allen wrench) set, get them with ball ends. The advantage is that their ball end make it easier to slide the wrench into the receiving slot. You can reach in at an angle and feel your way to the needed drop-in position faster. Good for blind or inaccessible places. It’s a small thing, not worth replacing other hex wrenches for, but if you need to buy some hex wrenches, these ball ends are better. Different brands make them in many varieties, format, and handles.