in what colors are these phones available?
In gold, silver, and space gray.
IPhone 6
 The back is built of 6000-series aluminum. Both models come in gold, silver, and "space gray" finishes. 
how big is the screen on the iphone 6s iPhone 6 display is 4.7 inches in size. what are some of its battery features? The iPhone 6 features a 6.91 Wh (1810 mAh) battery, iPhone 6 Plus features an 11.1 Wh (2915 mAh) battery, neither of which are user-replaceable.
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IPhone 6 [SEP] Design
The design of the iPhone 6 and iPhone 6 Plus is influenced by that of the iPad Air with a glass front that is curved around the edges of the display, and an aluminum rear that contains two plastic strips for the antenna. The back is built of 6000-series aluminum. Both models come in gold, silver, and "space gray" finishes. The iPhone 6 has a thickness of , while the iPhone 6 Plus is in thickness; both are thinner than the iPhone 5c and iPhone 5s, with the iPhone 6 being Apple's thinnest phone to date.