RC track border

This is a good track border marker for touring or drift cars used on a smooth surface. They are meant to be connected together with braided mason string that is available at all hardware stores or on Amazon (https://www.amazon.com/MARSHALLTOWN-Premier-Line-ML339-Fluorescent/dp/B001RJ6YSK/ref=sr_1_5?crid=2BAPT0VFJ2PTG&dchild=1&keywords=braided+mason+line&qid=1612314277&sprefix=braided+mason%2Caps%2C177&sr=8-5).