This unassuming and unadorned band looks very plain, but fairly expensive. The platinum band has a single tiny diamond inset into it, flush with the surface of the band. The diamond may or may not glow dimly when found. The ring magically adjusts to fit the wearer's finger perfectly.
When the wearer uses a bonus action to toss an object into the air and snap their fingers using the hand with the ring, the object disappears. The ring of storing transports the object into an extradimensional space for storage. When the wearer uses a bonus action to snap their fingers again, the object reappears above the ring and drops into their hand. The diamond glows faintly when the ring has an item stored, not enough to see by, but enough to be noticed.
Creative users can swap items by throwing one item into the air and snapping their fingers to retrieve the stored item. The thrown item disappears, replaced with the item previously stored. It's a simple magic trick, but an effective one. The wearer gains no knowledge of the type of object stored in the ring, so pranksters have been known to store rotten fruit or extremely fragile vials of acid to trick their friends or punish thieves.
The ring can only store a single item up to 10 pounds, and no dimension of a stored object can be longer than 5 feet. It can store a sword, but not a polearm. It can store a bag of coins, but not a handful of loose coins. The extradimensional space doesn't contain enough air to sustain a tiny living being for more than a minute.