While affordable and available everywhere, these aids are best used in the city where there are some ice and slippery areas. The problem with them was their tendency of slipping off the shoes. Perhaps the rubber did not encase the shoe properly? I see quite a few stray rubber devices around on the sidewalks - and I have almost lost mine myself in the snow while going through the woods. They provide some traction and are lightweight, but expect some slippage. Will not purchase again.