An open cutter for a foil type shaver includes a plurality of arch-shaped cutting strips formed by bending a metal plate formed with alternating parallel slots and cutting strips. The run count value for a particular one of the devices may vary according to a total load of the particular one of the devices. A strip of resilient material is directly bonded to the sheets around the perimeter thereof, so as to seal the gap between the transparent sheets and to provide a seal between the window insert and the window opening.