If you're ever in an area without cellular reception, satellite is going to be one of your only reliable options to communicate with the outside world. Over the years, wireless carriers have introduced satellite connectivity, making it available to phones that have the necessary hardware. That's where this Garmin inReach Messenger Plus accessory comes in, providing satellite communication to virtually any device that runs Android or iOS. While it's normally $500, it can be had for 40% off right now, dropping it to $300 for a limited time. I've had plenty of close calls hiking back in the day when I wish I had some type of satellite device with me.