WBTC input identity and handling
Wrapped Bitcoin is classified as a wrapped asset for this route. WBTC uses a wrapped contract asset on Base. The Base side is contract-tracked rather than a native gas balance. WBTC leaves through a custodial wrapper contract with token approval and source-chain gas; no native Bitcoin UTXO is spent by that transfer.
Base to Arbitrum L2 handoff
This route crosses two L2 execution environments. Base settles to ethereum, while Arbitrum settles to ethereum; each side keeps its own gas balance, token contracts, transaction hash, and settlement progress.
WBTC unwrap or exchange input check
WBTC is a custodial tokenized Bitcoin representation on smart-contract networks. Its transfers use token contracts and approvals rather than native Bitcoin inputs and outputs. On this route WBTC is the source token on Base. Its token balance, approvals, and contract transfer behavior are separate from the native coin used for network gas.
Arbitrum destination execution
Arbitrum is a L2 EVM network in the Ethereum ecosystem. ETH pays destination-side network gas on Arbitrum. EVM 0x account address An Arbitrum receipt appears on the Nitro L2 ledger under an Arbitrum token contract or native ETH balance; later spending needs Arbitrum ETH while L1 settlement continues separately.
WETH output identity and receiving
WETH is classified as a wrapped asset for this route. WETH uses a wrapped contract asset on Arbitrum. The recorded Arbitrum representation uses 18 decimal places. WETH arrives as a token contract balance. It may need an explicit unwrap before becoming native ETH and cannot itself pay transaction gas.
Base source execution
Base is a L2 EVM network in the Ethereum ecosystem. ETH pays source-side network gas on Base. EVM 0x account address A Base source transaction is sequenced on the OP Stack rollup and later settles to Ethereum; Base ETH and Base token approvals remain on the L2 ledger.
EVM-to-EVM execution boundary
Base and Arbitrum can use the same 0x address syntax, but they are separate networks with different chain identifiers, gas balances, token contracts, and transaction histories. The recorded settlement context includes ethereum, so L1 and L2 confirmation behavior should not be assumed identical.
Mistakes specific to WBTC Base to WETH Arbitrum
Route-specific mistakes include sending on a network other than Base; using a destination that is not valid for Arbitrum; running out of ETH before the source transaction is submitted; treating a wrapped token as the native gas asset. A Base source transaction is sequenced on the OP Stack rollup and later settles to Ethereum; Base ETH and Base token approvals remain on the L2 ledger. WBTC leaves through a custodial wrapper contract with token approval and source-chain gas; no native Bitcoin UTXO is spent by that transfer. An Arbitrum receipt appears on the Nitro L2 ledger under an Arbitrum token contract or native ETH balance; later spending needs Arbitrum ETH while L1 settlement continues separately. WETH arrives as a token contract balance. It may need an explicit unwrap before becoming native ETH and cannot itself pay transaction gas.