extra protection

The iphone white comes in the ipod white familiar to users for a several years now. Porcelain smooth white body with an elegant glass touch screen framed by a hi-tech chrome frame. There's a couple of discreet silver buttons - one for switching off the volume and the other's purpose escapes me.
My gripe is the little white plastic cap on the sim card cradle, the material on this bit feels out of place with the rest of the body.