The Leaky Cauldron’s Best-Kept Secret Behind the dusty shelves of Quality Quidditch Supplies and the flickering candles of the Leaky Cauldron lies a magic even Dumbledore might envy: the SR626SW—a 6.8mm silver-oxide charm, small as a Galleon but mightier than a Patronus. While flashy lithium-ion packs brag in Diagon Alley, this button cel