This Columbia Zither was manufactured by the Phonoharm Company, incorporated in 1891 in Maine but having their factory located in Boston. Phonoharp was one of America's four main fretless zither manufacturers, the others being the Menzenhauer Guitar-Zither Co. the Oscar Schmidt Company, and the Marxochime Colony. The company's namesake instrument featured a chord-grat attachment allowing the player to simply strum across the grate to produce each individual chord. This is their 6-chord model. This is their largest model #4. A unique feature to this zither is that it has two soundholes.