Maxsa 20024 Reflective Safety Band with 4 LED Lights Can be used on backpacks, arms, legs, on bikes, or to keep your pants from getting tangled in yourbike chain! Be seen from up to 1/2 mile away Highly reflective fluorescent material and lights that can stay on continuously or flash 150 times perminute Flexible band with Velcro closure for easy one-handed use Included replaceable CR2032 lithium battery lasts approximately 150 operating hours Each LED is 0.125" in diameter