RV Temperature Monitor

last summer i bought a marCell 500 cellular monitoring system off amazon. it only needs power and a cell phone signal to work. doesnt have to be a strong signal, just enough to make a cell call. no internet needed except to go to their webpage to register and set limits and notifications it plugs into a 110 outlet but if power cuts off it has a rechargeable battery backup for a period of time. it monitors temp and humidity. you pre set your temp and humidity limits high and low range. if temps go out of range you receive texts (my iphone and my wifes iphone, both our emails, and both receive automated phone calls so there is a great system. its not cheap 199.00, and i think a yearly subscription is 99 bucks, but we travel with 4 small dogs. we don't usually leave them alone in camper more than 3 or 4 hours at a time but its cheap insurance to be notified if temps get into the hazzard zone. we always stay close enough to campground to return in an emergency situation. i can say that it works as its supposed too. after breaking camp, turning off a/c in summer, then heading down the road towing, we receive alert that power is out, when temps get past our setting which is 82 degrees towing down the road, we receive alerts.