Apple has unveiled that its Watch collection will range in price from $349 to $17,000 depending on the metals they are made from and the straps they are bought with.

The larger 1.7in models of the Watch will cost about $50 more than the 1.5in versions in the lower-priced ranges.

Apple also revealed that the devices are due to go on sale on April 24.

Competition’s smartwatches have only seen limited sales to date.

A press event held in San Francisco held few surprises about the wearable tech beyond the fact that the mid-range stainless steel edition would start at $549 and go up to $1,099 in the US.

There had been speculation that Apple would seek a bigger price gap between the model and the basic aluminum-based Sport-branded version – something that would have restricted its appeal.

Apple’s website lists a total of 38 models, which might pose a challenge to how it markets them.

The company did not announce any difference in specifications between the aluminum, steel and gold-cased versions – there had been speculation that the higher-end editions might have more storage or allow some of their parts to be upgraded at a later point.

Apple CEO Tim Cook said the Watch would typically last owners 18 hours between charges, providing a day’s worth of use.

Its website adds that the models take 2.5 hours to charge from 0% to 100%, and that the larger model has longer battery life.

Apple also reveals that a Power Reserve facility means that the Watch should continue to show the time for “up to 72 hours” after other functions are turned off.

The company said on stage that thousands of new apps had already been developed for the Watch ahead of it going on sale.

The social networks Facebook and Instagram, the car pick-up service Uber and the Chinese messaging app WeChat are among those confirmed to have developed software for the device.

Apple also highlighted that its wrist-worn device could be used to make touchless payments and receive phone calls.

Other functions demonstrated by Apple included:

• using the Watch as a means to open a compatible hotel room lock as an alternative to a key card
• checking the name of a song via the app Shazam
• opening an internet-connected garage door remotely

To provide many of its functions – including GPS tracking, receiving phone calls and transmitting messages – the Watch requires its owner to have an iPhone 5 or more recent Apple handset, limiting its potential audience.

Even so, one expert believes sales will be strong – at least initially.

CCS Insight forecasts 20 million units will be sold by the end of this year – representing about 7% of the compatible iPhones currently in use.

However, other analysts range widely in their predictions, forecasting sales as low as eight million units to as high as 60 million in 2015.

For comparison’s sake, the iPad sold 14.8 million units in the first nine months after its launch, more than double Wall Street’s most optimistic estimate.

The UK, US, France, Germany, Japan, Australia and Canada are among the first wave of countries where Apple Watch will be sold.

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