Your controller drives power to your motor and controls its speed, so it's important to replace it if yours becomes damaged or broken. We'll get the correct replacement to you so that everything will soon be in working order again. Do you know where is the controller in?In the box , which is under the battery. You need to open it by unscrew the nut. NAKTO electric bike controller for mini cruiser SKU:D050043S Specification:NJT4825-1 Model:This NAKTO battery suits for those NAKTO ebikes:Mini Cruiser If you still do not know which NAKTO bike controller you need buy,please check with our customer service. Email:[email protected] Shipping:The product usually be dispatched at the same day that orders received, and it usually takes 3-7 days to be delivered. Enjoy free shipping on your order over $100. And we only ship to the US.