I'm pretty sure that it's a welt (sc). It's an upholstery thing, they use it on the edges to give it a nice, clean look. Makes the edge look nice instead of just leaving it empty and unfinished. You can make it yourself if you have a sewing machine, if not, then just go to any upholstery shop and they can make it for you for the cost of material. It's really easy to make, you just have to go to any craft store & buy welt. It comes in many thicknesses, so just pick the size that you want, then buy the material that you want to wrap around it. You wrap the material around the welt (like a taco
) and just sew right next to the welt so it doesnt move. Then you just staple it to the edge of the board and presto, you're done.