The bottom side of the mount is left open to fit a GoPro

Blackburn has really thought out the spec of this tool to make it suit Moutain Bikers needs

There are 2

and gave it a price tag that speaks more to the Wednesday Night Championships

Preventive measures:

Hope eBike Speed Sensor Magnet - Speed Sensor Magnet - Red - 6 Bolt - R24mm NoAusPost The bottom side of the6 bolt mount Speed Sensor Magnet for eBikes. Available in two options R24mm & R32mm, use the document below to find out which one will fit your e bike. eBike Sensor Position Chart Features: 6 bolt rotors, Std or floating compatible Two sizes: R24mm & R32mm Available in Black, Silver, Blue, Red, Orange or Purple Comes with 2 bolts NOTE eBike manufacturers use a vast variety of magnets to interact with the sensor. These magnets can vary in size, shape