It looks like a large wooden dowel that someone stained a dark color. You can find those wooden dowels at places like Michael's and Hobby Lobby, or Home Depot and Lowe's. You can buy finials to attach to the ends. You could also buy a decorative curtain rod with finials and cut it down to a shorter length.

Here is a link that might be useful: Kudzu's Blog

I agree w/ Kudzu, the more fancier ones are curtain rods....

Macrame looks nice tied onto driftwood, too. But yes, that's a stained hardwood dowel. When you buy one, look down the length of it and turn it, check for warping.

You can also use wooden beads on ends of painted or stained towel, or ceramic or even metal beads. Imporant thing to remember is the dowel should match size of project. In the pic shown the project could be 18 in. long then need 1/2 to 3/4 in dowel. If it's only 8 in. long then need probably 1/4 in dowel. I made xmas trees 1 yr & used 1/4 dowel across the bottom with red wooden beads on ends glued on. Driftwood is excellent choice for top of macrame hanging item. The dowel used to come in about 36 in. lengths & would be box of them with dividers for the different sizes,ask where they are at or you'll probably miss them. Not too expensive either. Of course if people come around & stick a flag in your yard for 4th or with flower attached for Mother's day advertising homes for sale, their bottled water, etc. Then get dowel free!!Could cut down a left over brass or white round curtain rod & put metal decorative beads on ends(file ends of metal smooth so don't get cut) Wooden hobby horse handle too!! Good Luck! Jan