The Ring of Reagents, also known as the Ring of Shal, appears in Ultima VII Part Two.
Wearing it, the caster no longer has need for reagents, since the ring always provides necessary reagents for any spell cast. The Ring of Reagents was created by Shal with the aid of the Chaos Serpent, at the cost of Shal ‘losing himself’ to pure chaos and becoming the creature known as The Fiend.
The Avatar heard of this ring upon travelling into Serpent Isle's past, in the midst of the War of Imbalance. The Fiend told the Avatar of the ring, which he wanted to possess at any cost. Searching through the tunnels, the Avatar found the ring, but, realizing the Fiend's evil intentions, would not hand it over. The Fiend attacked the hero and was subsequently destroyed.
It is unknown what happened to it after the Avatar left the Serpent Isle.