Validating Zip Code

I was recently putting together some proof of concept for a customer and realized that I hadn't posted one of the common Regular Expressions that I had been using.

Validating a Zip Code:

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        ' Invalid Zip code
'Dim strZip As String = "AB123"

' valid Zip Code
       Dim strZip As String = "03110"

      Dim regexp As New Regex(("^\d{5}$"))

      If regexp.IsMatch(strZip) Then
                   MsgBox("Zip Code")
                  MsgBox("No zip match")
     End If

End Sub