Nilfisk BV1100 Commercial Backpack Vacuum Cleaner Double Pole Switch
It will suit many other backpacks, including Origin, Rocketvac and Pullman.
SAFETY WARNING! All electrical parts should ONLY be fitted by an electrically COMPETENT person.
At the moment, standard postage is capped at a maximum of $25 within Australia, so maximise the saving on postage and buy something in the related parts below!