Black MDF Twin Slot Shelving Set

Does anyone know if twin slot shelving is a standard ? I have some brackets from B&Q but they didn't have the tracks in stock Screwfix do but

Twin Slot Black Brackets · DB120B Sapphire Twin Slot Shelving Bracket 120mm Black · DB170B Sapphire Twin Slot Shelving Bracket 170mm Black · DB220B Sapphire

twin spin slot Black MDF Twin Slot Shelving Set Looking for a chic and versatile shelving solution for your crib or workspace? Enter the Black MDF Twin Slot Shelving Set -

twin slot bracket Twin Slot Bio Coat Uprights offer secure and flexible shelving solutions suitable for various environments Their antibacterial coating makes them resistant