Green Spokelit is easy to attach, no tools required. Replacable batteries & Durable. Stays secure even in off road conditions. We have sold hundreds of these since the Washington Post showcased these in their Gift Guide section last year. Now we have lowered the price. The Spokelit provides added safety & fun for anyone that rides a bicycle. Easy to turn on and off and provides both Flash & Constant On Modes. Great gift idea!