Claim: Reference works are used by iPhones.

7 / 7 Plus :  -RCB- -RCB-  | unitssold = 1 billion +   | service =  -RCB- -RCB-  iPhone -LRB- -LSB- ˈaɪfoʊn -RSB- -RRB- is a line of smartphones designed and marketed by Apple Inc. . They run Apple 's iOS mobile operating system . The first generation iPhone was released on June 29 , 2007 , and there have been multiple new hardware iterations since .   The user interface is built around the device 's multi-touch screen , including a virtual keyboard . The iPhone has Wi-Fi and can connect to cellular networks . An iPhone can shoot video -LRB- though this was not a standard feature until the iPhone 3GS -RRB- , take photos , play music , send and receive email , browse the web , send and receive text messages , follow GPS navigation , record notes , perform mathematical calculations , and receive visual voicemail . Other functionality , such as video games , reference works , and social networking , can be enabled by downloading mobile apps . , Apple 's App Store contained more than 2.2 million applications available for the iPhone .   Apple has released ten generations of iPhone models , each accompanied by one of the ten major releases of the iOS operating system . The original 1st-generation iPhone was a GSM phone and established design precedents , such as a button placement that has persisted throughout all releases and a screen size maintained for the next four iterations . The iPhone 3G added 3G network support , and was followed by the 3GS with improved hardware , the 4 with a metal chassis , higher display resolution and front-facing camera , and the 4S with improved hardware and the voice assistant Siri . The iPhone 5 featured a taller , 4-inch display and Apple 's newly introduced Lightning connector . In 2013 , Apple released the 5S with improved hardware and a fingerprint reader , and the lower-cost 5C , a version of the 5 with colored plastic casings instead of metal . They were followed by the larger iPhone 6 , with models featuring 4.7 and 5.5-inch displays . The iPhone 6S was introduced the following year , which featured hardware upgrades and support for pressure-sensitive touch inputs , as well as the SE -- which featured hardware from the 6S but the smaller form factor of the 5S . In 2016 , Apple unveiled the iPhone 7 and 7 Plus , which add water resistance , improved system and graphics performance , a new rear dual-camera setup on the Plus model , and new color options , while removing the 3.5 mm headphone jack found on previous models .   The original iPhone was described as `` revolutionary '' and a `` game-changer '' for the mobile phone industry . Newer iterations have also garnered praise , and the iPhone 's success has been credited with helping to make Apple one of the world 's most valuable publicly-traded companies .