Arbitrum (ARB) perpetual futures on Polymarket track the spot price of Arbitrum in USD, with no expiry. ARB is the native token of Arbitrum, an Ethereum layer-2 network that uses optimistic rollup technology to execute transactions off the main chain and post the results back to Ethereum. Arbitrum is developed by Offchain Labs, founded in 2018 by Ed Felten, Steven Goldfeder and Harry Kalodner, and ARB, launched by airdrop in March 2023, is used to vote on proposals in the Arbitrum DAO. Offchain Labs grew out of research at Princeton University, and its Arbitrum Orbit framework lets teams launch their own chains on the Arbitrum stack.