Hi Mate, this is ' GAP' insurance and it makes up the difference from what your insurance pays out and what the car is actually worth at the time. The insurance co. will only pay up to a limit for what they think its value is, not its true value so the GAP insurance makes up the difference. Definitely worth it and you can pick it up quite cheaply if you look online, think mine was less than £200 for 3 years cover.