These things are AWESOME! I bought them to add weight to the edges of canvas drop clothes (part number BD08-0912 purchased here) that I wanted to use as outdoor furniture covers. I was worried the magnetic field wouldn't penetrate the heavy canvas. Boy did I worry needlessly. These things stuck to each other through the canvas like glue. I placed a pair about every 18 inches around the perimeter of the canvas, locked them in place with straight pins so they wouldn't slide on the slick canvas…