Retrieving Instance store volumes using AWS SDK

I'm currently trying to retrieve a list of all the volumes associated with a given instance. Using the JS SDK one can do so via the following snippet:

const params = {
  Filters: [
    {
      Name: 'attachment.instance-id',
      Values: [ "my-instance-id" ],
    },
  ],
};

let { Volumes } = await this._ec2.describeVolumes(params).promise();
console.log(JSON.stringify(Volumes, null, 2));

however, to my surprise, that leads to a list of only the EBS volumes. Is there any other way of retrieving the list of ephemeral devices associated with my instance?

By the way, it looks like you also can't easily get that from the console (at least I didn't find).

Am I looking at the wrong place? The reference for describeVolumes is here: http://docs.aws.amazon.com/AWSJavaScriptSDK/latest/AWS/EC2.html#describeVolumes-property

Also, querying the the instance meta-data properly reveals the presence of the ephemeral device:

curl http://169.254.169.254/latest/meta-data/block-device-mapping/ephemeral0
sdb

Thanks!