Quote Originally Posted by t_marat
Sorry, but what does "copping" mean?
Copeing with means to deal with.

Also the description is a bit misleading. It is a check valve that maintains high vacuum in the power booster. You will notice the little arrow embosed on it, this points in the direction of air flow, which is from the booster to the engine. This valve allows you to have full power brakes in the event that the engine stalls or in low vacuum situations. If the power booster fails, the engine will draw air from it and you will have a large vacuum leak.