Are twin slot brackets strong enough to support a shelf layout?

Twin Slot Shelving Hanging Rail - Uni-Shop twin slot rail Unlike Single Slot Systems, Twin Slot Shelving provides double the amount of slots, providing stronger bracketing, better weight distribution and ultimately, a twin slot shelving ikea Genuine twin slot system

twin happiness slot Bracket and holder with snap lock for 25mm hanging rail suitable for hanging storage under a solid wood or melamine shelf; Recommended maximum load 30kg at