NW-S645K

The NW-S645K is the speaker-equipped 16 GB model in the seventh-generation S Series Network Walkman. It carries the new x-app software and expanded integration. It features 16 GB flash storage supporting MP3, WMA, AAC, and WAV playback, video and photo viewing, the 240x320 TFT display, 42-hour battery, WM-PORT, Clear Audio, DSEE, Lyric Pita, x-app, and built-in speaker.

This Walkman model was another example of Sony extending a stable late-S platform into retail-friendly variants without needing to touch the core identity. This is part of the phase where the S Series was broadening its appeal without fully losing its focus.