The MINI Power Brake Booster Vacuum Line is one of the parts that you just need, when you need it. We have never seen a line fail, but what happens is your working in the engine bay and the line breaks the nipple off at the check valve. As these cars get older, the plastic can get brittle due to age and heat. This makes the line useless and makes stopping the car a lot harder. Sometimes you can glue it back together to get by for a bit, but it only lasts long enough till the new line arrives. Comes with everything needed to do the job correctly so that you have brakes when it matters. We always have one in stock just in case.