CREE Q5 Led 240 Lumens bike Bicycle Head Light Torch Mount Holder Set (Blue) Length: 11cm (no-stretch)and 12cm (stretch) Diameter: 3.2cm (head) and 2.6cm (rear) Material:high-quality metal aluminum Three modes: high, middle, strobe. Zoomable design. Battery: 3 x AAA (not included)