Ultra-bright LED's that clip on to safety spectacles Light a dark area while protecting your eyes and keeping your hands free for working. 2 x CR2032 lithium batteries can be easily changed. 2 clip sizes included for easy assembling on all 3M Safety Glasses The 3M Headlight Spectacles are ultra-bright LED's with long battery life (over 50 hours), that are easy to fit and are compatible with most safety spectacle frames. Shine light into a dark area while protecting your eyes and keeping your hands free for working.