It is just a regular nut, covered by a rubber cushion. it is not likely you'll find other applications. If you can devise a way to cover the nut and protruding bolt, like a rubber hose covered by duct tape it may not look very pretty but would be a lot cheaper. You may check in an Auto Parts store for rubber plugs which could be epoxied over the nut, but the black rubber may leave marks. If you can get a couple of seasons out of those , $8 plus tax & shipping is not too bad.