Sheldon Coopers 'Spectrum' Shirt

This BDG brand shirt, while once sold by Urban Outfitters, is now gone without a trace. Apologies for failing you, dear shirt-hunters.

Featured on The Big Bang Theory episodes

S01 E12: : "The Jerusalem Duality"
S02 E17: "The Terminator Decoupling"
S03 E21: "The Plimpton Stimulation"