The Cateye Wearable X Rear LED is a must have for any commuter. The Wearable X is one of the easiest & most versatile ways to improve your visibility to other road users. You can simply attach it to your clothing or rucksack with a one-touch, detachable clip, or directly to your bicycle via the included rubber strap. Getting dark on your commute? Wear it. COB LED (35 lm) Low profile round shape Clip-on bracket for easy installation to backpacks, saddle bags & clothing Li-ion polymer rechargeable battery USB (Universal Serial Bus) rechargeable (Micro USB (Universal Serial Bus) cable included) Low battery indicator 6 modes * Charging time: 2h Mode memory function Battery Auto Save (Lighting mode automatically changes to slow flashing when the battery power gets low)