An apparatus for wrapping batches of products for insertion into a carton includes a lifter for lifting a batch from a first height to a second height at which a pusher pushes the batch into a tunnel toward a loading zone along a direction of movement, a station for feeding wrapping film to a folder that supports and guides the film around the tunnel; a longitudinal sealer configured to join two longitudinal flaps of the film to form a tubular shape; a transverse sealer positioned close to a rear end of the tunnel for joining the top and bottom flaps of the tubular film; and a pair of panels for containing/retaining the batch coming out from the tunnel; the panels being slideable along respective side walls of the tunnel to modify the operating length of the tunnel.