A Belgian stone with two natural sides is what you will need.
Do not purchase the stone with a black side. You want either the brown/blue/purple speckled side for the coarse side and the tan/cream/yellow for the fine side. With that stone you would be able to maintain your razor indefinitely.

Both of the sides need to be used with a slurry so be sure and purchase a 2 sided slurry stone or a naugura stone.

Hope this helps,