Niteize NiteHowl LED Safety Necklace to keep your head down and alert to changes of temperature. This is made to withstand the most extreme conditions. Dimensions: 9 mm x 3 mm x 3 mm, 20.7 l x 12.6 l Weight: 5.8 ounces to 7.0 ounces (12 x 6.3 x 11 x 2 cm)