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

Help me find this bracket how to build this shelving system white twin slot shelving White TwinSlot Steel Shelving Kit: 2 uprights, 4 shelves & 8 brackets Ideal for offices, schools, laboratories, storerooms & retail stores white slot Organising and storing items, tools or parts is easy with slot shelving Comprised of three parts: uprights, brackets, and shelf boards

white rabbit slot demo Twin Slot Shelving Upright - White - 1220mm This Heavy Duty Wallbar is versatile and durable