The rear battery lamp from brompton is a genuine replacement brompton rear light it has a built in reflector and is designed to replace your rear reflector on your rack or y shaped bracket on the rear brake by using a genuine brompton light on your brompton it allows you to be able to fold your bike up without having to worry about the lights interfering with anything the light has 2 modes on and off and is both shock and water resistant it gives great visibility reaching up to 400m away