- Attach this guide easily on your safety helmet. - Make secure a safe workplace (especially in the dark place) - Length of Guide: 130mm X 13mm, there are emitting lights in 3 places and you can easily find it in the distance. - It is suitable helmet for mining, road construction, guards of traffic safety, harbors, tunneling work and roughing in constructions. - It can use more than 100 hours by 1ea of Lithium battery(3V). (The using of re-chargeable battery is more economic.)