The Amazon Echo, an internet connected speaker that has voice control that will respond to questions, is about to go on general sale in the US.

The device has only previously been available as a private invite product since its launch in October, but is ready for the big time. Amazon told Pocket-lint of its American availability during a chat in London.

Slightly larger than a carton of milk, the speaker works in a similar way to the "OK Google" feature on Android phones. You can ask the Echo speaker questions or control devices in your house through a series of voice commands.

Amazon says that it has been able to make the Echo available for sale to everyone because it has finally fulfilled an order backlog that had been created. The device was hugely popular during the invite-only trial period when offered towards the end of last year. Those who ordered previously should now have their speakers.

The Amazon Echo is now available on pre-order for all US customers. They can order now for $179.99 at www.amazon.com/echo. It will start shipping to customers from 14 July.

Amazon hasn't as yet confirmed whether the Echo will be coming to the UK.