U2464 Turbopower 2 with 'Autosense' - you turn it on and push it around and have to play with paper bags, but get a little speaker that listens for grit and boosts the power intermittantly.
You can of course turn the boost on yourself, through the other button ....
U2466 Turbopower 2 with 'Autosense' & 'Permabag' - you turn it on and push it around, but dont have to play with paper bags!
Instead you get a permabag container - fill it up and tip it out, making sure you have your back to the wind!
As with U2464, you get your little speaker as well...