This variation of the famous Model B Graphophone shares the same tiny open works motor, upscaled to play the large 5" diameter Concert or Grand cylinders that had come on the market around 1898. However, the AB can also play conventional 2" cylinders by unscrewing the knurled nut, removing the 5" Concert mandrel, and raising the telescoping interior 2" mandrel to reach the reproducer. (See also the Columbia Type AD.) At $25 this was the cheapest machine made which could play the soon-to-become obsolete Concert records, which had dropped in price from $5 each to $1 apiece -- still a considerable sum for the time. (This phonograph was the third I ever bought, back in 1962!)
With the large mandrel removed the machine could play conventional cylinders. The lid is very ornate, typical of Columbia's handiwork at the turn of the 20th century.