This is an Artbitrum node that is fully used for transaction records, in which user transactions are recorded based on the order of the transaction in which they come before they are executed according, and submitted to layer1. Transactions are bundled in batches before they are submitted to the blockchain.

This sequencer helps reduce the gas fees for each transaction since transactions are bundled together before being sent to L1. it is cost-efficient and fast transaction.
Sequence submission of transaction: for a bundled transaction, each transaction in the bundle is in order of which they are sent in a well-organized manner.

Limitation of Sequencer
To run the sequencer, it must be run with its own security assumption.
Transaction bundled transaction can be discarded if they have yet to be executed.
Transactions are not updated instantly on the l1 blockchain, not until the bundled transactions are updated.
Sequencers can be centralized since the bundled transactions are processed off-chain before they are been processed on-chain. During the process of off-chain computation, the sequencer network can be attacked.