Different reasons why people call items "B" stock. Here's my experience: the manufacturer may have either slight blemishes (i.e. finish is slightly off), or it may have been used as a demo by the manufacturer or the importer/rep. So long as the tiem is presentable (and believe you me, I'm picky, no reason not to go for it and save a few bucks. The "B Stock" term is used loosely, but, either way, you can't go wrong...
