The power for the tail light is simply tapped from the main battery by fitting in its plug before attaching the headlight. Despite the great brightness of the tail tight, this only diverts a minimal amount of energy and only reduces the burn time of the headlight by a few minutes. The tail light can be controlled by the standard Supernova headlight unit. You can choose between constant light-on or flashing mode. The tail light continues to burn with full brightness for hours even after the headlight has gone out so it also serves as an emergency safety and signalling light. With its 20-50 inch (50-120cm) spiral cable, it can be used on every frame and with practically every positioning of the battery. The tail light can be securely fixed to anyseat post of diameters up to 35 mm.