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

Are twin slot brackets strong enough to support a shelf layout? white twin slot shelving Purchase 2400mm white twin slot shelving uprights for modular shelving systems Available in various sizes and colours white twin slot shelving White Twinslot Shelving

white twin slot shelving Complete shelving kits with white slotted-steel uprights, white shelf brackets and beech or melamine-faced chipboard shelves

white rabbit megaways slot Twin Slot Shelf Upright 710mm White  Product Detail The Twinslot Shelving system is designed as a simple 'upright & bracket' arrangement, for supporting various types of timber shelves