Amazon Alexa Guard is a free service that enables your Echo device to listen to signs of danger and warn for you. Amazon Guard Plus is a new upgrade service that expands Alexa Guard features and capabilities, like give a siren when detecting an activity inside the home, or motion is detected outside, even auto-call the emergency Helpline from your Echo device. Guard Plus is a paid service. The service will cost $4.99 per month or $49 per year. The service works with all generations and configurations of Echo devices that include Echo Dot, Dot Kids Edition, Clock Echo Dot, Echo Spot, Echo Plus, Echo Show, Echo Flex, Echo Studio, and Echo. Now Amazon offers a 30-day Free service for subscription to Guard Plus> Offer limited time.