Maybe you're a sleep deprived PhD student working on a theory no one has ever heard of. Maybe you just want to LOOK like a sleep deprived PhD student.Either way, we want you to look your best with this Math Proof Chalkboard Bow Tie. Wear those equations with pride. 100% Silk. Standard 2.5 inch bow with adjustable neck sizing from size 14 to 20. Very limited edition