The formulation ```(but still usable)``` is not very clear. I think something like this would be more appropriate.

```
AWSSDK use the aws-sdk node module that wraps all the HTTP requests to SES servers.
If running on an Amazon EC2 instance, it allows the use of IAM Roles instead of AWS credentials.
If necessary, the AWS credentials can still be provided to the *createTransport* method or through environment variables ( AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY ).
```