The NEBO GLOW Light + Handle not only makes your 30 oz. or 20 oz. tumbler easier to hold and carry, but also gives you the power of light without moving a finger. No more slipping, dripping or tripping in the dark while trying to balance your tumbler when your hands are full. The GLOW fits most standard vehicle cup holders, and perfectly holds your tumbler secure with the rubberized grip ring. Needs AAA batteries. NOTE: Handle only, tumbler not included. Made for 30 oz. tumblers, fits 20 oz. tumblers using included attachment