Unknown Tile Maker    circa 1920-1940       Attractive yet practical vintage ceramic vent tile.   Vent tiles, also know as grilles or grates, were made mainly to accommodate heat exchange.    They were used in fireplaces and other architectural installations.   Some were used to artfully mask floor drains or as ceiling vents in a shower.   Measures 6" x 6" x 5/8" thick.    Very good condition.