The present invention relates to a rear finisher for smoothing an outer surface, which is attached in the forward direction behind a device for outdoor preparation and particularly for snow piste preparation. In order to allow a uniform appearance of the piste surface, the rear finisher has a guide device, which is applied so that the material to be prepared is guided in front of the bottom of the rear finisher and subsequently smoothed thereby. Furthermore, the present invention relates to a method for smoothing an outdoor surface, in which the outer surface to be smoothed is smoothed by two different oscillating means guided one after another on the outdoor surface.