SLDW or Super Loss Damage Waiver is the additional insurance to protect the renter from the excess fees if there is an accident and you are at the default.

if the renter does not purchase additional insurance (SDLW) and there is an accident and you are the default or do not have a third party, the renter needs to be responsible for damage according to the rental contract of the car company you have signed. Usually, you only pay an excess amount as a maximum amount.