Rechargeable LED Bike Lights Set, FuPany Waterprooof Bicycle Headlight(White) Taillight(Red) Combinations LED Front Back Cycling Flashlights Head Rear Lamp, 4 Light Modes, 2 USB Cables
These are great, charge quite quickly, fast to take in and off and fit in your pocket/bag with ease meaning you don't have to leave them on the bike at all times.