Facebook has introduced a pair of camera-equipped devices – the Portal and Portal Plus – in an attempt to gain a physical foothold in people's homes. The artificial intelligence-powered hardware is primarily designed for video-calling and features a 12-megapixel camera that is able to follow people around the room. Using AI, its cameras can zoom and pan as people move around, making sure the camera always has its user in its sights. The smart home devices – which feature Amazon's Alexa voice assistant – are currently only available for pre-order in the United States, with the Portal costing $199 and the Portal Plus costing $349. Similar to smart speakers like the Amazon Echo and Google Home, the voice assistant on Facebook's Portal devices is always listening in order to capture commands.