Easily installed by plugging one end to your Bafang controller in the appropriate plug and the other end on the handle of your brakes.
See video instructions on how to install here: https://www.youtube.com/watch?v=dlvBxedXTZ8
Can also be used with mechanical disc brakes as well for those who want to use the Bafang stock ebrake handles.
The sensors work fine for mechanical breaks. The electrical plug connections work well. They are tight but do pull apart rather than break under tension.
After putting my bike together, I rode around for a couple of weeks without brake sensors. I have to say that the sensors are a very valuable part of the system - they make riding much safer and more pleasant and even extend the battery range. They work well and seem stable now that they're on, but I removed one star because they were pretty fiddly to install. I didn't have too much trouble getting the distance right, like some previous reviewers, but they were not well suited to the shape of my brake levers (Shimano deore XT), so a lot of glue was required. If you have these I don't think a gear change sensor is required, because the brake sensors can be used kind of like a clutch, switching the engine off momentarily while the gears change.
I have Shimano 315 hydraulic brakes, it took ages to configure the magnet and sensor position - very sensitive to exact position by a quarter millimeter, the magnets and sensors only work through perpendicular vertical movement past the sensor head, large movement to activate so sensor only active once the brakes are full on so I am braking before motor cuts, sensor glue pads no longer sticky enough so holding sensor on with electrical tape, holding magnets on levers using electrical wire heatshrink, looks crappy and cheap, does not do the job properly, complete waste of money.
These brake cutoffs work perfect but can be a little be fussy to fit to some brakes. I have SRAM Guides and took me a lot of attempts and superglue to work out the best spot to mount the sensor and magnet. Check the forums for ideas, that helped me.