That is actually a piece of a wooden rod that was in a closet in my house - we redid the shelves in the closet so this was just sitting around. It's about 1.5 inches in diameter, so it's not too big, but it's actually pretty comfortable to hold.
I did drill a hole through it (used a 7/16 inch spade bit) and passed the rope through the hole before I knotted it but you can't tell from the picture.