Rune nails

Rune Nails is a members-only item on the OSRS Grand Exchange in the runes category.

In-game examine text: "Keeps things in place fairly permanently."

It has a Grand Exchange buy limit of 13,000 every four hours, a high alchemy value of 132 gp, and item ID 4824.

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Rune Nails shows an active flip setup with a margin of +43 gp and 610,466 trades over the last 24 hours.

At the buy limit of 13,000 every four hours, max profit per cycle is about 559.0k gp — high margin with healthy liquidity.