Capitalize all Letters in Column B..rows will Vary

Heres one from my colection of other peoples code! i think this came from mrexcel

Sub UpperCase()
    
    Application.ScreenUpdating = False

    Dim cell As Range
    For Each cell In Range("$B$1:" & Range("$B$1").SpecialCells(xlLastCell).Address)
        If Len(cell) > 0 Then cell = UCase(cell)
    Next cell
    
    Application.ScreenUpdating = True
    
End Sub