Timm Holt makes sure his house is safe and secure. "What I have in my home I have three floors and they all interact with each other," Holt said. But having working smoke and carbon monoxide alarms doesn't necessarily mean you're safe. Sites including Amazon have been selling these alarms not tested and certified by nationally recognized testing centers. "You know I wasn't surprised too terribly much," assistant chief of fire prevention and building safety Craig Snyder said. "I was surprised that Amazon had as many of them on their listing as they do." Snyder says there's 23 products manufactured by eight different companies on Amazon right now. "That's a pretty high amount," Snyder said. Wisconsin requires all smoke and carbon monoxide alarms are properly certified before hitting the shelves.