In southern Arizona, temperatures can quickly climb into triple digits making the journey in the desert a challenge.
Piles of black jugs line the border as undocumented immigrants get their last ounce of water before illegally coming into the United States.
There are nearly 50 miles of rural land to get through before any sight of life.
"It is pretty desolate here in Three Points a little south there is really not a lot down there, there are no restaurants, gas stations there is not really any water anywhere especially natural water so that can be a danger for people crossing the border," said U.S. Customs and Border Protection agent Christopher Sullivan.
Running out of water, food, and then energy CBP's rescue beacons are a chance of survival.
The Tucson sector has 34 rescue beacons and to use it a person just has to press the button or pick up a satellite phone.
When a beacon activates agents respond.
"The purpose of that cell phone is to kind of like to say if someone needs help they can push the button call us and tell us the extent," he said.
CBP states from May to July this year over 200 people were rescued from heat exhaustion and just 19 of those used rescue beacons.
Despite temperatures reaching 120 degrees in the desert, CBP says that is not even a deterrent for those crossing.