This power pack is an original Samsung product so it would definitely not do you wrong. The plastic is a very good quality hard case, may increase depth of overall phone by 2 to 3mm and 1 cm at the bottom, but the battery pack performs very well. Said to give 250mins extra talk time with 3G. Light on the accessory notifies you of the batterys remaining content and has a button at the bottom which does this. Would have been nice in white. Professional quality product that is made in Korea -jay^^