The one piece of plastic sticking on your sony xperia z's screen is NOT a screen guard.Since Sony is not using gorilla glass they have gone cheaper way ,by adhering some sort of plastic covering.Actually the sony logo is on the front plastic sheet,so if you remove it you also permenantly lose the logo too.I was originally thinking "how nice of sony to add an extra screen guard in the pack" infact those screen guards need to be applied before start using the phone.The plastic film prefitted once scratched ,can not removed I think,some people who tried to do that have ended up smudging thier screen.This information is from a retailer who recently had attended workshop conducted by Sony 