Samsung  has unveiled the Galaxy Fold foldable phone at an event in San Francisco, live streamed to an audience in London. Announcing the phone, Samsungs senior VP of product marketing, Justin Denison, said the device “doesn’t just define category, it defies category”.

When folded, the phone has a 4.6-inch display. Unfolded, the screen size expands to 7.3 inches. One neat feature of the phone is what Samsung calls App Continuity: when a user fires up an app on the screen in folded mode, then unfolds it, the same app is displayed, larger, on the unfolded screen.

It also features three app multitasking. When the screen is unfolded, the user can have three apps running simultaneously, one occupying around two thirds of the unfolded screen area, the other two stacked on top of each other in the remaining third of the screen. Holding one of the two smaller apps swaps it over to the larger display area.

The Fold features 12GB of RAM, 512GB of onboard storage, and no less than six cameras – three on the back, two inside and one on the front. It is powered by two batteries and will come in LTE and 5G versions. The Fold goes on sale on 26 April, with prices starting from $1,980  (£1800), a price point that drew gasps from the London audience.

Samsung’s president of mobile, DJ Koh, said the Fold break news ground because it answers the skeptics who say the era of smartphone innovation is over. “We are here to prove them wrong” he said. “No company has done more to put the smartphone at the centre of our mobile connected lives…For those who think they have seen it all, I say: ‘Buckle your seatbelt, the future is about to begin.’”

Samsung also unveiled the Galaxy S10 at the event. It has a camera with an Instagram mode to upload photos and videos to Instagram with one click from the camera. It also has a Wireless Powershare feature that enables the phone to be used to power another phone, watch or other  compatible device.

It comes a larger version, called the S10+ and a more compact version, the S10e. It is available to pre-order from today. A 5G version of the phone will be available later this year.

On the wearables front, Samsung also announed the Galaxy Watch Active smaertwatch, with 60,000 clock face options and the Galaxy Fit activity band.