Peter and I just did a little test with the Griffin ClearBoost case on an unadulterated AT&T iPhone. The results, while far from conclusive, showed that with the case on and your hand over the antenna, near the bottom of the unit, the ClearBoost case allowed the phone to maintain a fairly strong signal. This does not mean you’ll have better call quality or faster Internet, per se, but it does mean that the ClearBoost is doing something to improve cell tower reception when you hold the phone up to your head.