# TransactionInput A transaction input — a reference to a previous output ([`TransactionOutPoint`](/documentation/BitcoinKernel/TransactionOutPoint)) plus the scriptSig and witness data that unlock it. ``` final class TransactionInput ``` ## Overview Inputs are obtained from a [`Transaction`](/documentation/BitcoinKernel/Transaction) via [`input(at:)`](/documentation/BitcoinKernel/Transaction/input(at:)); there is no public `create` initializer because inputs are only meaningful in the context of a signed transaction. Wraps the opaque `btck_TransactionInput` type; `deinit` calls `btck_transaction_input_destroy` when the last Swift reference drops.