We've bought a dozen of these over the past four years. Every single one of them failed. Every. Single. One. The "lock" mechanism is too finicky. Not only is it hard to get the system to stick/lock, but once you THINK you have, it falls down too easily, regardless the material it's up against (drywall, tile, painted plaster, brick.).The engineering of this product is exceptionally poor--which is remarkable for a non-electronic modern product.See full review