The new iPhone 4 produced high-quality glass and stainless steel. It is 34% thinner than the iPhone 3GS and only 3 grams heavier … According to Apple, it’s the thinnest smartphone on the market. They shared volume buttons are also made of stainless steel in Unlike the current iPhone 3GS.
video at the end is really useful, for someone who want to know details about iPhone 4.
yupp this detail tells about the full features of new iPhone 4.