I used this on my bicycle, but I no longer need it, so I'm selling it. Functionality has been confirmed. This is being sold as-is, and returns and refunds are not possible. Please understand that this is a used item before purchasing. The following is the product description: GIZA CG-406R Auto Function Tail Light A rear light with an auto function that automatically turns on/off via a light sensor and vibration sensor. ■0.5W Red LED ■4 modes: Auto On/Auto Flash/On/Flash (On: 18 hours, Flash: 36 hours) ■Includes a saddlebag clip ■L36.5 x W32 x H70mm ■33.5g (excluding batteries) Bicycle Tail light Tail lamp Red light