Highly Reflective, light-emitting vest-like belt system. Battery source is two AA batteries. Very reflective even without light on. The light is VERY VISIBLE in the dark. Picture the color of a Turquoise Neon Sign. Lighted verticle strips are on the front and back and can be set for solid (non-blinking), speedy blinking or very speedy blinking - think of the movie TRON. This belt system officially is Large/X-Large or one-size fits all. The belts can be reduced to fit a Small thru an XX-Large. In our store, customers are buying them for Ragnar (run through the night) runs/races, where they intend to share the reflective light-emitting belts and that way each "vest" isn't a sweaty mess, since this goes on the outside of whatever you're wearing. It would be fine to wear bear chested. Great for cross walk guards as well!