# InputObject
You can use an `Object` as an argument, and GraphQL calls it an `InputObject`.
The definition of `InputObject` is similar to [SimpleObject](define_simple_object.md), but
`SimpleObject` can only be used as output and `InputObject` can only be used as input.
You can add optional `#[graphql]` attributes to add descriptions or rename the field.
```rust
use async_graphql::*;
#[derive(InputObject)]
struct Coordinate {
latitude: f64,
longitude: f64
}
struct Mutation;
#[Object]
impl Mutation {
async fn users_at_location(&self, coordinate: Coordinate, radius: f64) -> Vec<User> {
// Writes coordination to database.
// ...
}
}
```