FLM 4EVER CVD KIT LOSI DBXL HARDENED STEELWe use our exclusive heat treat process and material combination that we developed over years of research and development. We are so confident in the shaft we stand behind it with our warranty. If it bends or breaks we replace it. (does not cover wear - if it held up through numerous beatings it did its job well) We designed these with durability in mind. The stock 4mm pin is just not up to the task. With our 5mm pin setup you can have peace of mind knowing that whether you are out in the yard or out on the track you will finish the day without a broken shaft.