You get what you pay for here, and these are as described. If you have the budget though, I'd highly recommend getting the hydraulic brakes with the e-cutoffs built in. If on a budget, these will have to do if you want to keep your existing brakes. My one magnet broke in half just by me handling it normally (they are neodymium and really powerful), but I was able to keep using it by fitting it back into a circle and taping it together. I lost my other one after it bounced away and clinged to something. It takes a lot of finese installing these, as well as an epoxy or strong glue, and you have to get the positioning JUST right, but otherwise they are pretty straightforward to install. You'll want to install these once your battery and motor are all hooked up.