Crash protection devices are designed to break when overtravel forces are exceeded and prior to any damage being caused to the probe. For use with TS27R, OTS or RTS. The support bar is used to hold the stylus in place, while tightening the grub screws holding the stylus in the stylus holder. It is also used to steady the stylus holder while tightening the cap head screw that holds the stylus to the probe via the sheet steel retaining plate.