“Solder is the glue of the modern age,” says Kyle Wiens, co-founder and CEO of repair manual website iFixit. But many people are worried about using soldering irons to fix their personal tech—for good reason. They’re hot, expensive, and can be dangerous. “The initial brief was, What can we build into the hardware to make it much, much easier than any soldering iron that’s come before?” says Wiens.