Currently it is not possible to buy additional insurances with hvv switch. When booking a SIXT share, MILES or WeShare car via the hvv switch app, only the booking with the standard liability limit is possible. Details about the liability limit you can find out at the respective partner.
Good to know: Only the functionalities of the connected partner services offered in the app can be booked via hvv switch. Offers, packages or vouchers of the mobility partners can generally not be used or booked via hvv switch.