Ethereum Rollups are a layer-2 scaling solution that allow for off-chain transactions to be executed and then batch-verified on the Ethereum mainchain. This results in increased transaction processing capacity, lower fees and faster confirmation times compared to on-chain transactions.

In a Rollup, transactions are executed within a smart contract, called the "rollup contract", that is deployed on the Ethereum mainchain. The smart contract keeps track of all off-chain transactions, and periodically "rolls up" the information into a single on-chain transaction. This batch verification process enables many off-chain transactions to be processed with just one on-chain transaction, thereby increasing the overall scalability and efficiency of the Ethereum network.

Additionally, Rollups can also provide enhanced security as they use zk-rollups, a form of zero-knowledge proofs, to ensure the validity of off-chain transactions without revealing any sensitive information.