Microsoft's Zune music player has gone on sale in the US, hoping to make a dent in the success of Apple's iPod.
The Zune comes in three colours - brown, black and white
The modest launch of the player is Microsoft's first direct attempt to topple the iPod, which dominates the MP3 player market around the world.
The Zune is only available in the US and there is just one 30GB model - in three colours - for $250 (£131).
The Apple iPod has a 75% share of the digital music player market in the US and more than half of the world market.
Microsoft has all but abandoned plans to try to topple the iPod by working with third-party MP3 player manufacturers.
The firm licenses software called Plays For Sure, which guarantees that digital music bought from a range of download stores works on players that have signed up to the system.
But Microsoft's Zune is not part of the Plays For Sure initiative - so songs bought from Napster, Rhapsody, AOL or Urge, for example, will not work with the player.
Songs bought from Microsoft's own MSN music store - which is being closed down - will also not work on a Zune player.
30GB model - $249
3-inch screen (320*240 pixels)
Songs cost 99 cents or unlimited subscription for $15 a month
Two million songs on offer
Wirelessly share songs with other Zune users
Registered guests can swap songs via a PC
Instead Zune users must buy and download music from a dedicated Zune music store - or rip their own CDs and copy them on to the player.
Zune owners can buy individual tracks using a points system - 79 Zune points equals 99 cents which buys a single - or subscribe to the service monthly, giving users access to two million tracks.
The first reviews of the player have been mixed - praising some features, and criticising others.
"The player is excellent," wrote David Pogue in the New York Times.
"It can't touch the iPod's looks or coolness, but it's certainly more practical.
"It's coated in slightly rubberised plastic, available in white, black or brown, yes, brown.
"It won't turn heads, but it won't get fingerprinty and scratched, either. It sounds just as good as the iPod."
Walter Mossberg in the Wall Street Journal wrote: "Zune has several nice features the iPod lacks: a larger screen, the ability to exchange songs with other Zunes wirelessly and a built-in FM radio."
The unique selling point of the Zune is the ability to wirelessly connect to other Zune users to share songs - one song can be shared three times and will only be stored on another Zune for up to three days.
But the practical limitations of the sharing option - even listening to part of a shared song counts as one listen - has been criticised by the early reviewers.
The limitations are presumably in place to prevent wholesale sharing of songs but the protection even applies to songs not downloaded or bought.
"What's really nuts is that the restrictions even stomp on your own musical creations," wrote Pogue, describing the protection as "draconian" and "as strict as a 19th-Century schoolmarm".
Both reviewers criticised the lack of other features in the Zune.
Pogue wrote: "It doesn't have a single standard iPod amenity: no games, alarm clock, stopwatch, world clock, password-protected volume limiter, equaliser, calendar, address book or notes module."
You cannot download podcasts either, he pointed out.
Three core models - Shuffle, Nano and iPod colour
30GB iPod ($249)
2.5-inch screen (320*240 pixels)
Songs cost 99 cents
iTunes users can share songs over a network
Can download and play podcasts
Extras such as calendar, notes and alarm
"This first Zune has too many compromises and missing features to be as good a choice as the iPod for most users," wrote Mossberg.
He added: "The hardware feels rushed and incomplete."
Mr Mossberg also criticised the payment scheme for the Zune marketplace, pointing out that users have to buy £5-worth of points at a time, even if they intend to buy only a single track.
Zune users must use a new piece of library software - and not Windows Media Player.
Sadly, the two writers pointed out, Microsoft does not let music lovers share libraries across computers on the same network; one of the features of iTunes.
But Zune users can share their library with an Xbox 360 games console.
Mossberg concluded: "Overall, the iPod and iTunes are still the champs.
"Still, I expect the Zune to attract some converts and to get better with time.
"And this kind of competition from a big company with deep pockets and lots of talent is good for consumers in the long run."