Strong enough for smoothies and with frozen fruits. The glass jug is thick without giving you the feeling that it will easily break. It is easy to clean as the blades unscrew and can be washed separately. The only downside is that it unscrews with the movement of the blades, so it can come loose from the many vibrations (very tightly screwed) especially from frozen fruits. It also has a hole that if the jug opens, the liquids pass through there and go directly into the motor. They could have put the blades or the motor to work in reverse.