If you use it the proper way, Let it sit level in the paint, to cover the pad , pick it up & wipe off excess ,Put to wall about a foot below area ( at a 45 degree angle) Push of to area to be painted, Roll it down the line , with little pressure. If the surface is un even lower the pad as much as you need to make a straight line. 

TheCrazyMonkey

Port Saint Lucie, FL