Until recently they used to be known as Mark's Work Warehouse - mostly, as the name implies, clothes, work boots, jackets, vests etc. for workers engaged in physical, outdoor, or factory type occupations, plus they carried some casual clothing (big on jeans and sweaters and coats). They changed their name to Mark's in order to expand on the more casual side of the market though I'm not sure they've yet gone into more formal wear like suits and jackets. Just about everything else but that, I think .