No one probably cares but... Actually the force of suction doesn't exist (or so I've been told), but rather it's the force of atmospheric pressure that holds the robot onto the wall. So the bigger the so-called suction plate the more surface area there is for atmospheric pressure to hold the robot onto the wall. That's why people are blown out of a spaceship instead of being sucked out of a spaceship. So, FYI, this robot would probably not work in the pressureless so-called vacuum of space. However, I'll bet cleaning these windows without the aid of this robot would really suck.