The big souvenir shop by Fenway Park... you know - before you go in on the corner of Yawkey Way. I buy a team pack of baseball cards there every year. It was created by a pair of brothers, twins Henry & Arthur D'Angelo who started out selling felt pennants then moved into hats and more; Twins Enterprises. If you crawl eBay you'll know that name... Their family grew up working in the store and semi-recently relaunched as '47. Clever collab right now with Carhartt and '47 on some iconic hat shapes to celebrate opening day for both Detroit and Boston. The trusty watch cap, and a 'Sox flavored duck 6-panel.
Read much more about it http://blog.47brand.com/carhartt-x-47-outwork-x-outroot/.