Tail Lights are designed to keep traffic off your back, unfortunately that same light quickly becomes a nuisance if it's too bright. Because of that, NiteRider's Stinger USB has four modes. That may seem like overkill for a tail light, but consider a peloton situation with bright, flashing tail lights. As they do for oncoming headlights, eyes need to adjust and vision, not to mention sanity, is compromised. To address this, the Stinger is able to kick output down considerably with a group ride mode in both steady and flash settings. In the steady high setting this 25 lumen NiteRider will last around four hours, and when in group ride mode it'll last around 16 hours both flash settings net around 10 and 16 hours respectively. A USB charging interface quickly and conveniently tops off the lightweight 250mAhr battery in less than two hours. Finally, a rubber strap securely attaches the Stinger USB to round and aero seatposts alike.