The LG G2 is the successor to the LG Optimus G and the first LG smartphone to arrive after the end of the Optimus era. The G2 smartphone was launched in August 2013 but had already been much talked about because the hardware buttons are on the back, not the sides. LG has also included a number of innovative software features on the G2, such as "KnockOn," which allows the user to turn the screen on and off simply by tapping it. The 5.2-inch Full HD display has almost no margin and the 13-MP camera with optical image stabilizer is another special feature of the G2. The processor is a quad-core Snapdragon 800 with a 2.2 GHz clock speed.