Bafang BBS system brake sensor pair is used in an installation where the brake levers are not required, or not practical. You can use your existing levers with this product. This product is only for BBS Bafang products.
Does your existing bike have hydraulic brakes or integrated shifters? It might not be practical to use the standard BBS brake levers with e-brake switch. If that's the case and you would still like the safety of e-brake cut-off, then you need to install these sensors onto your existing levers. Checkout our conversion kit manuals for an example of this installation.