Geist Watchdog 100-P Environmental Monitoring System Environmental factors like heat, humidity and moisture pose a severe threat to mission-critical infrastructure. These dangers can be minimized by incorporating a network of environmental sensors to collect data and alert users of potential threats. Adding optional sensors to a Vertiv Geist Environmental Monitor or Rack Power Distribution Unit (rPDU) allows users to observe conditions from a secure Web interface and receive alerts via Email, SNMP, or Email-to-SMS.