E.R. Butler & Co.

"The showroom, in the original Tiffany & Co. silver department building, is not only a stunning space, but it offers an encyclopedia array of hardware options from all styles and periods—they have the largest collection of hardware catalogs in the world. Along with their own gorgeous line, they also carry designer objects from Ted Muehling, Hella Jongerius, and Philip Crangi, a few of which they manufacture, too."