Box trap

Box Trap is a members-only item on the OSRS Grand Exchange in the other category.

In-game examine text: "If a creature goes inside, the box should then slam shut."

It has a Grand Exchange buy limit of 250 every four hours, a high alchemy value of 19 gp, and item ID 10008.

View on OSRS Wiki

Box Trap shows an active flip setup with a margin of +13 gp and 24,921 trades over the last 24 hours.

At the buy limit of 250 every four hours, max profit per cycle is about 3.3k gp — high margin with healthy liquidity.