Rain bow

Rain Bow is a members-only item on the OSRS Grand Exchange in the weapons category.

In-game examine text: "Short but effective and very colourful."

It has a Grand Exchange buy limit of 18,000 every four hours, a high alchemy value of 300 gp, and item ID 23357.

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Rain Bow shows an active flip setup with a margin of +43 gp and 453 trades over the last 24 hours.

At the buy limit of 18,000 every four hours, max profit per cycle is about 774.0k gp — high margin with healthy liquidity.