C # Identify a removable hard drive

using System;
using System.IO;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void BtnFind_Click(object sender, EventArgs e)
        {
            foreach (DriveInfo drive in DriveInfo.GetDrives())
            {
                if (drive.DriveType.Equals(DriveType.Removable))
                {
                    MessageBox.Show(drive.Name.ToString() + "is an external derive.");
                }

                else
                {
                    MessageBox.Show("Not external drive avialible");
                    return;
                }
            }
        }
    }
}