Each set includes four tuning screws for wheels with bearings, for use on Techdeck/Arctic trucks. Normal tuning screws do not fit through the hole in the bearings, so if your axle fell out, you were out of luck, untill now. The bearing screws from Flatface will fit through any wheel with a bearing. Because the screws have threads, rather than being a smooth axle, they help the bearings to operate correctly. The threads actually grip onto the inner core of the bearing, causing the parts inside the bearing to spin rather than the bearing acting as a metal core. Many people find that bearing wheels with these screws roll faster and longer. NOTE: Because the threads are smaller on these screws in order for them to fit through bearings, they may not screw into most trucks. The best way to fasten them is to put the screws through the wheel, then put a dab of epoxy or any other strong glue such as super glue, and (very carefully) put the screw into the hole in the truck, and let it dry. Make sure you don't let the glue get on the wheel. For any bearing wheels, bearing tuning is the key to get the best possible performance. $5 per set of 4 stainless steel bearing screws.