5‑mm flat head screwdriver or Pozidriv screwdriver (PZ2) To remove the EGW501 cover, unscrew the fastening screws (4 pcs) and lift the cover. Use either a 5‑mm flat head screwdriver or a Pozidriv screwdriver (PZ2). Remove the Vaisala SIM card and insert your own SIM card into the highlighted SIM card slot. Put the cover back in place. Tighten the screws until the cover makes good contact with the surface of the enclosure base.