WesTech GAC contactors can be supplied in an open-top gravity system or, more commonly, in pressure vessels. They are typically designed with a conical underdrain for convenient GAC replacement.
By contrast, the HomePod is essentially an extension of the iPhone, like an accessory. When someone asks the HomePod to open a third-party app, the request wonât go directly to the cloud, as with the Echo, but to an iPhone. As a result, developers can't write apps for the HomePod. They must create tweaked versions of existing iPhone apps.
Apple Inc. audio engineers had been working on an early version of the HomePod speaker for about two years in 2014 when they were blindsided by the Echo, a smart speaker from Amazon.com Inc. with a voice-activated assistant named Alexa.