In an October 5 post to its Facebook page, altimeter manufacturer Larsen & Brusgaard announced that it had discovered a problem with some batches of filters for the Ares II altimeter, which would restrict airflow and cause erratic changes in altitude readings. Replacing the battery cover (which contains the filter) with an unaffected cover should resolve the issue. Users can also puncture the filter by pushing a pin through the central hole of the cover, although the unit will no longer be waterproof. Ares II dealers and owners may contact Larsen & Brusgaard with any questions at hello@lbaltimeters.com. The full Facebook post that contains details about the issue is available here: facebook.com/lbaltimeters.