# Smart Contracts ### Overview The Charged Particles protocol consists of a series of smart contracts, but there are four primary smart contracts that control the majority of the logic and are the only ones required to integrate with: ***ChargedParticles.sol*** > The primary contract for interfacing with the Charged Particles protocol. This contract controls the logic for viewing and updating a Particle's balances / nested assets. ***ChargedSettings.sol*** > Used to view and update rules for how the Charged Particles contract functions. ***ChargedState.sol*** > For viewing and setting permissions, approvals, and time locks on Particles. ***Proton.sol / ProtonB.sol*** > The Proton contract is the base NFT of the Charged Particles system. It is a standard ERC-721 NFT with some added functionality. \ > \ > ProtonB provides the exact same functionality as the Proton, but has some minor changes for gas improvements, and was rolled out for V2 of the protocol. ### Latest Contract Addresses The addresses to the 4 primary Charged Particles contracts can be found in the respective V1 and [V2](https://docs.charged.fi/charged-particles-protocol/developing-on-the-protocol/smart-contracts/v2) sections of the docs, along with links to block explorers and source code. Additional contract addresses can be found in [**this npm package**](https://cdn.jsdelivr.net/npm/@charged-particles/protocol-subgraph@latest/networks/)**:** The complete list of our contract addresses includes "helper" contracts associated with the four primary contracts of the protocol, contracts associated with our [IONX rewards](https://rewards.charged.fi) program, and some legacy contracts that are no longer used. To check what the latest version number of the protocol subgraph npm package is, check [here](https://www.npmjs.com/package/@charged-particles/protocol-subgraph).