This tie's got so much chemistry, even Bill Nye wears it. Remember learning how many H's you needed for every O? Forget H-2-O, you're going to make it rain in this OoOTie! We chose the colors on this periodic table of elements tie for a reason. Chalk boards were once green and some of us remember the days of white chalk. This is more than just a classic - it's a time piece. 100% Silk. Standard 2.5 inch bow with adjustable neck sizing from size 14 to 20.