Quickly find the right socket size even when engraved socket size labels are worn or dirty. Built-in sizing bolts help you quickly measure the socket size INSIDE the working end. Simply place the socket on the bolt and see if it fits. If it doesn't, move up or down a size. In a matter of a second, you have sized your socket. *** Please note that sizing bolts help you find the right sized socket – they're not for socket storage. Bolts are too short and sockets will fall off! *** Please measure your drawers before ordering to make sure the tray fits your needs. *** Please note that SOCKETS ARE NOT HELD in place by clips or magnets in this organizer. The tray is light and portable but sockets will fall out if turned upside down. Check out reviews by The Humble Mechanic and The Protool to see and hear what experts think!