The display is 4 inches (diagonal). The glass front is flat. The back is anodized aluminum with matte chamfered edges and a stainless steel inset logo. The Sleep/Wake button is on the top of the device. The Home button has Touch ID. There's a True Tone LED flash on the back and a SIM tray on the right side that holds a "fourth form factor" (4FF) nano-SIM card. The IMEI is etched on the back cover