# Introduction

##### Sell an NFT at a fixed price#

The Asks Modules allow for the sale of an ERC-721 at a fixed price. You can view the code for all Asks Modules in this GitHub Repo.

### Mainnet Deployments#

##### Ethereum - 1#
CoreETH0x34Aa9CBb80dc0b3d82D04900C02FB81468DafcAb
CoreERC20Soon ™️

### Testnet Deployments#

##### Ropsten - 3#
CoreETH0x032e29122873bE11F7885ed636b1f06135D6A033
CoreERC20Soon ™️
##### Rinkeby - 4#
CoreETH0xA8389b0FBe3508bB10925D9f0C1618d0DaF54c74
CoreERC20Soon ™️

There are several variants for the Asks Module. Each variant comes with different features and associated gas costs.
• An ask can be created by an owner or approved operator for any ERC-721 token.
• There can only be one ask open at a time for a given NFT.
• Creating an ask for an ERC-721 token requires that the owner has previously approved the ERC-721 Transfer Helper for it to be valid.
• Royalties are paid out using the Manifold Royalty Registry when an ask is filled.