People living in homes with spotty Wi-Fi may feel tempted to throw out their routers, switch providers, or even move. But researchers at Dartmouth College have discovered a more practical alternative that costs less than a month of internet. As EurekAlert reports, a sheet of metal and plastic can vastly improve the reach of a home’s Wi-Fi coverage.

The 3D-printed device is inspired by an even cheaper home hack that’s been around for a while: By placing an aluminum can behind their router, some people claim they can reflect wireless signals away from walls, furniture, and other obstructions. In place of a can, the new research presented at ACM's BuildSys 2017 in the Netherlands relied on technology that’s slightly more sophisticated.

Using a special algorithm, the team customized the designs of their reflectors to compliment the spaces they worked in. A program called WiPrint analyzed this data and manufactured the optimal shape using a 3D printer. The plastic product then had to be wrapped in regular aluminum foil and wedged behind a router for the effects to work.

This process offers another benefit on top of directing Wi-Fi coverage to certain rooms: You can also choose to redirect it away from some spots, like your neighbor’s house, for instance. Making a customized reflector this way currently costs around $35. If you don’t have your own 3D printer for making fancy router accessories, here are some even simpler Wi-Fi boosting tips you can try right away.

[h/t EurekAlert]