AS Elisha Palmer settled into life at home with a newborn baby, she thought she had all bases covered.
While it was the new mum's first child with her husband, the 36-year-old had two healthy older children already, so thought she knew what to expect.
But when her son Knox was just three-months-old she put him down for a sleep one day and he never woke up.
The newborn from Iowa, US, died in his sleep from Sudden Infant Death Syndrome (SIDS), which is something that has no cause or explanation.
"He was completely healthy," Elisha told People magazine.
"He just went down for a nap and didn't wake up. There was nothing that would have been a red flag.
"We did everything we were supposed to do," she added.
"There's not a word in the dictionary that exists to describe the pain when you've lost your child.
"I kept saying I don't know what to do with my arms.
"My arms are empty. He was always in them."
The mother-of-three blames herself for her son's death.
The 36-year-old believes if she had paid up for a high-tech baby monitor, she may have been able to prevent Knox's death.
Elisha says she knew of baby monitors that measure both heart-rate and breathing of little ones while they sleep.
However, the mother-of-three says she didn't think she needed it.
"I had two older kids who were healthy. I didn't think this would happen to us."
"I carry that guilt of why didn't we get one," Elisha said.
"I feel like if he had one there is such a good chance he would be here with us and so our ultimate goal is that no baby goes without this device."
Now to honour her son's short life, the family have created a foundation in his name - Knox Blocks.
They are raising money to buy these high-tech monitors to give away to families who can't afford them, in the hopes to prevent another child from dying needlessly from SIDS.
In the US, it's the largest killer of infants under the age of one.
While in Australia, 54 babies died of SIDS in 2013.
In the seven months since Knox's death, the Palmer family have raised $33,000 to give away Owlet monitors.
When the CEO of the company heard about the family's story and what they're doing to prevent SIDS, they joined in and offered to match every dollar raised by Knox Blocks.
"No parent should experience that grief and heartache," CEO and co-founder Kurt Workman told People.
"We were, and still are, so touched and inspired to see all that the Palmers were doing to honour his memory."
An Owlet spokesperson told Kidspot the monitors are not yet available in Australia but should be sold Down Under towards the end of the year.
This article originally appeared on Kidspot and has been republished here with permission.