For parents, knowing their child is safe can be one of their biggest worries. Parents of children on the autism spectrum may worry even more.

But tracking children may not be enough in an emergency.

AngelSense, an app and wearable device, was updated last week with a new feature for such emergency situations called First Responder Alert. The feature pings parents about the location of their child, as well as data on how long it takes them to leave and arrive at certain locations.

The GPS tracking and alert system was developed by parents Doron Somer and Nery Ben-Azar, who both have children with autism and were searching for a better way to keep track of their whereabouts.

See also: 5 Autism Simulations to Help You Experience Sensory Overload

The wearable GPS tracker — a small rectangular-shaped, sensor-filled box that fits into the pocket or attaches to clothes via its internal magnet — and an app collects location data every 10 seconds and can send text alerts to parents when it senses the child's phone is moving. The device includes a microphone so parents can listen in to get an idea of the situation; according to AngelSense's website, the battery can last from 12 to 14 hours.

With one click, parents can send a text to a list of contacts with details about the child’s location, including Google Street View images and directions to get there.

The AngelSense Guardian app updates users with location information, maps and Street View images.

According to a 2012 study in Pediatrics, 49% of parents with a child on the autism spectrum said their child attempted to wander or run away after the age of 4. Wandering can lead to a multitude of dangers, including traffic hazards and drowning. The National Autism Association recorded 32 wandering-related deaths in 2015.

"I know exactly how families feel and have experienced [this before]," co-founder Ben-Azar told Mashable.

AngelSense first launched in 2014. The system has already helped save the life of a 17-year-old autistic child from the Bronx, and the co-founders said that the child, Hanzel, left his home and drifted around Manhattan and Queens. Hanzel's mother was able to use the new First Responder Alert to locate and get him back home safely with the help of others.

Earlier in 2015, a 15-year-old girl with Asperger syndrome was kidnapped near her home in Dallas, Texas.

"AngelSense sent the mother an alert that the girl went to an unexpected place," Somer, one of the cofounders, said.

The mother used the listen-in feature of the device and heard a struggle as her daughter was assaulted.

"The [kidnapper] saw the tracker on the girl and asked her what it was," Somer added. "After she said 'it's a GPS tracker,' he insisted she take it off. But the girl told him only her mother could take it off with a special key, so the kidnapper ran away."

Her mother, Kathy Gilray, wrote about the experience in a blog post, citing that with the AngelSense's tracking information, police were able to track down the kidnapper.

The small GPS tracker can be attached to any garment with a magnetic lock, and communicates with the parent's phone. Image: AngelSense

However, it's certainly possible that so much access to a child’s location can create even more anxiety and cause parents to obsessively check on their child’s status.

There are other tracking devices similar to AngelSense, such as PocketFinder and Amber Alert GPS, but they are more easily removable, and many don’t have text alert features. For children who might remove their clothes, an AngelSense belt ($19.99) is available that can only be opened with a magnet.

The customer care team, which is available to help with questions or emergency situations, is made up of mothers active in the autism community who use the app, Ben-Azar said.

AngelSense is available for $59 until Jan. 31 and will cost $149 thereafter. The app is available for download via Android (Google Play link) and iOS (iTunes link).