Ring mould

Ring Mould is a free-to-play item on the OSRS Grand Exchange in the other category.

In-game examine text: "Used to make rings."

It has a Grand Exchange buy limit of 40 every four hours, a high alchemy value of 3 gp, and item ID 1592.

View on OSRS Wiki

Ring Mould shows an active flip setup with a margin of +279 gp and 1,069 trades over the last 24 hours.

At the buy limit of 40 every four hours, max profit per cycle is about 11.2k gp — high margin with healthy liquidity.