Custom Mahogany Base for 12" Marine Clocks. 19 1/4" tall, 18 3/4" wide and 7" deep. The clock mounting area is 15 1/4" in diameter. Mount your 12" marine clocks on these bases to beautifully display them on a shelf, mantle or any strong horizontal surface. The last photo shows a Waltham 12" Marine Clock on the base as an example.