The world is still focused on the new iPod Nano and Zune HD, but that didn't stop Sony from unveiling its thinnest Walkman ever on Wednesday morning. Sony's new NW-A840 Series measure just over a quarter of an inch thick.

The NW-A840 Series devices also offer a 2.8in WQVGA OLED screen, TV-out function that renders 720x480 standard definition video, FM radio, and digital noise cancelling. The NW-A840 series includes three models: the 16GB NW-A845; the 32GB NW-A846; and the 64GB NW-A847. Sony claims the new Walkman's battery life will be 29 hours for music playback and 9 hours for video, according to Sony Insider.

Unlike Sony's X Series Walkman, the new NW-A840 line-up is missing popular features such as a touchscreen and Wi-FI connectivity. But that's not surprising, as Sony is focused on creating a broader range of players than its competitors. Recent speculation has predicted Apple might end up doing away with its iPod Classic to focus on the iPod Touch and iPod Nano. Meanwhile, Microsoft has decided to discontinue its other Zune players in favor of the Zune HD. A quick glance at a few online retailers shows about eight different Walkman models from Sony, plus the recently released X Series -- the Zune HD and iPod Touch competitor.

The NW-A840 Series will be released in Japan on October 31, but there's no word whether its Australian equivalent will see a similar device lineup in the coming months. The NW-A840 Series shares similar features -- like digital noise cancelling and FM radio -- as the NWZ-S738F, which was released earlier this year.

Japanese pricing for the NW-A840 series ranges from US$263-$439, but those prices would likely change for the Aus market.