Satellite Communicator & GPS handheld device. This unit pairs with your cell or other mobile device and allows you to send email/text via satellite when you are outside of cell service. Exactly as per this link here: https://www.mec.ca/en/product/5053-916/inReach-Explorer%2B In addition to its satellite messaging function, it also functions as an extremely capable handheld GPS device, to include built-in topographic maps of North America. Use of the satellite messaging function is done on a subscription basis- so you will have to set the unit up and provide a credit card # to Garmin to enable you to use it. I have done a factory reset to clear my data and billing information from memory. This is an exceptionally useful device for anyone who works outdoors in remote areas. As you can see from the link provided above, these things cost almost $600 brand new. This one is in almost-new condition, and I'm selling it for about half price because I no longer have a work-related need to own it anymore.