InputBox Cancellation

I am having trouble with the Range type of Input Box being cancelled. I am using the code below and upon cancel I receive an object required message.
What am I doing wrong?

Dim xnbrs As Range
Set xnbrs = Application.InputBox(prompt:="Highlight Exhibit Numbers", Type:=8)
    If xnbrs Is Nothing Then
        Exit Sub
    Else
    For Each xnbr In xnbrs

Thanks in advance