Someone mentioned this in a post, so I looked it up and I'm considering getting one.
http://theanimalarm.com
Basically, it's a temperature monitor that you keep in your vehicle (or wherever) and it will text you when the temperature reaches a high or low temperature you set.
There's been a lot of discussion about leaving pets in vehicles in hot weather, and I think this would be a necessity for anyone traveling with their pet, especially pets like cats which you generally can't take with you when leaving your vehicle.
Probably won't help much if you are miles away from your vehicle, but you can always set the threshold a little lower to give you some time to get back before hitting the danger zone.
I wouldn't rely on this alone, but it's a good safety feature in the event that your AC goes out or your fan loses power.
You can buy it in the US from Critter Cozy for $169
http://crittercozy.com/Household-Safety/animalarm-temperature-sensor.shtml
On top of the steep price, you need to get a sim card from your cell phone provider, so it can access the cell towers.
I'm not sure if that means there will be a monthly fee or not, but can you put a price on piece of mind?
Anyone use one of these? Thoughts?