Sometimes, it’s the simplest ideas that make the biggest impact. The Koostik iPhone speaker uses an extremely basic idea to make your phone’s built-in speakers sound like a room-filling stereo system.

Using the same concept that gives acoustic guitars their oomph, Koostik is hand-made by a woodworker named Jim. The unique wooden amplifier uses no electricity at all – just the rich reverberations of natural wood.

As such, the makers warn that it’s not a replacement for powered speakers, and it’s definitely not appropriate if your music of choice is loud heavy metal. But fans of soft, warm vocals and instrumentals will enjoy the natural, unplugged amplification.

The value of the Koostik is not only in its ability to make music coming from your iPhone’s built-in speaker two to four times louder – it’s also a beautiful piece of decor that gives your eyes a nice little break from all of the plastic and shiny metal gadgets elsewhere in your house.