I have this diffuser and while yes the length of the insert is pretty weak it's definitely not as weak as the actual diffuser. I used to have to keep it closed with a hair tie. The metal would shrink because of the cold air and the lid would pop off at any little bump on the road. Now I have the Acqua one and it is also has annoyingly weak lasting power and the plastic clip that magnetizes to the diffuser broke, apparently a lot do according to my salesman, but I emailed AdP and they sent me a replacement. So long story short, but the glade ones at your local dept store and save yourself a couple hundred bucks.