Conclusion

For $34.90 the OS133 dongle sounds way better than listening straight out of a phone or laptop.

What really surprised me is the build quality – both wire & connectors wouldn’t feel out of place on a cable worth a few hundred dollars. I have no idea how Penon can make them for this price.

Sonically the OS133 is probably good enough for a noisy train ride, and more convenient than a conventional dongle which will bang up against your phone. Using the OS133 feels like plugging IEMs directly into your phone through an adapter, ergonomically it’s tough to beat and when price is taken into account is very easy to recommend.

I’d love to see Penon offer a few different wire choices as drop-down menu options, perhaps allowing a downgrade to cheaper wire or upgrading to pure silver for a different flavour.

The OS133 is perfect for max portability without the hassle of carrying & charging a separate device.