No recharge. Change the hole product after 10 years.
This seems at the first moment, not to be not a sustainable product. But there is another reason. After so many years, the vents will be dirty an the function isn't sure anymore perhaps. So it make sense to change the hole product for safty reasons. and - this product should be for safty reasons.
That was my opinion to buy this product.
(there ist an LED to warning about the battery is low)