Launched as one of the first major open source projects on Solana, Serum has a range of offerings:

Serum Core, an asset-independent order book to align with any Solana-based trading product. Serum’s back-end engine is ideal for both financial and non-financial instruments.
True interoperability — Serum’s architecture allows a variety of applications and participants to share middleware in one place.
Ecosystem and developer services — Serum offers a decentralized order matching service on the network, giving full control to developers. Serum DEX also offers a broader source of pooled liquidity.
Serum Token (SRM) — SRM is the utility and management of the Serum ecosystem and is fully integrated to benefit from buying/burning fees.
Solana Speed and Cost — Like Amulet, Serum uses Solana because of the extremely low transaction costs and speed of the platform.