Suction Cup Car Windshield and Vent Mount for PDA Smart Phone iPod iPhone Blackberry and treo - Universal fits everything from 50mm. to 90mm (1.9 to 3.5 inches) + Live*Laugh*Love Wristband!!!
It is wide enough to hold my iPhone (with a thick cover) easily.  It is very easy to insert the phone and lock it in place.  The arm is very stiff and minimizes bouncing the phone around.  It was very reasonably priced.  The only small issue is that the width is not wide enough to hold the iPhone in a landscape mode.  Very pleased with the product and the company who sent it.