34 "Sky Blue Windowpane Plaid Men's Slim Fit Two Button Suit" Classic Regular Fit Blazer Windowpane Pattern in Blue Suits Outlets THEORY Mens Blue Single Breasted, Windowpane Plaid Extra Slim Fit Suit Separate Blazer Jacket Mens Modern Fit Plaid Windowpane Suit with Double Breasted Scoop Vest Theory Suits & Blazers Theory Mens Chambers Burgundy Single. Theory is a new york based men's and women's contemporary fashion label which sells clothing and accessories. Theory uses many different fabircs such as wool or leather to emphasize the versatility and rich depth of the collection.