NW-S745K

The NW-S745K added speaker support to the 16 GB seventh-generation S Series Walkman. It incorporated the x-app software and tighter PS3/TV links. It offers 16 GB flash storage supporting MP3, WMA, AAC, and WAV playback plus video and photo along with the 240x320 TFT display, 42-hour battery, WM-PORT, Clear Audio, DSEE, Lyric Pita, x-app, and speaker.

The K version keeps that same cleaner S745 formula and simply repackages it for a more accessory-driven retail presentation. By this point the S platform is strong enough that Sony could comfortably build around it instead of constantly redefining it.