XINGCHENG Versatile mountain bike blinker + bicycle taillight + Horn + stoplights Multifunction Electronic bell combined turn signal light, taillight, electric horn and brake light in one. aillights mounted on the side-post (less than equal 27.2mm) controller installed on the handle (less than equal 25.4mm), installed brake light control knob on the front or rear brake cable. the cable length between controller and taillight is about 127 cm;Power by 2 x AA batteries (not included). It really is a perfect choice for the cycling enthusiasts.