Accessiores
Bumper
An iPhone 4 Bumper is a ring of rubber and plastic that surrounds the edge of the iPhone 4. The inner part is rubber with the external band made of plastic. The Bumper wraps around the edges of the device protecting the edges, and to a lesser extent, the screen. The Bumper does not cover the front or rear of the phone, though it does slightly raise the iPhone off whatever surface it is sitting on.[48]
Additionally, the plastic band houses metallic buttons for the volume controls and sleep/wake button. The six holes in the Bumper enable access to the mute switch, dock connector, headphone jack, speaker, and microphones.[48] The bumper also can be used to prevent the "antenna issue" that users face when holding the parts of the steel band where the antennas are, that could cause the phone's signal to drop.