WisHome Silicone Adjustable LED Armband Strap Wearable Luminous Arm Belt Reflective Running Gear Wristband LED Flashing Light Glow Safety Band for Jogging Cycling Walking Pack of 2 (Green and Yellow)

I think these are awesome! Hopefully they'll allow cars to keep their eyes on me when I'm running - though I guess they won't do much good with everyone looking at their phones :/

Very bright. Like the fact that there is both a steady and flashing modes.