A screw driver comes in all shapes and sizes and has a variety of features. There are flat head screwdrivers that are used for tightening or loosening flat head screws. There are Phillips head screwdrivers which are used for Phillips head screws. Even Torx head screwdrivers are used for securing items to avoid theft, like gym lockers. If you're looking to create a perfect screw driver set, you need to do a lot of research and understand your needs first. Any screw driver will do the job, but the best screw drivers are the ones that will stay in your toolbox forever. That is why professionals are picky about their screwdriver set. Some knowledge can be useful before purchasing any type of tool, but the market for screw driver is vast, making selection even more difficult.