You are bidding on a used OEM Secondary Smog Pump removed from a 2000 BMW 540i. This Item should fit all 540i and 528i  BMWs built from 1999  through 2001. It may fit other BMW models and years as well but you must refer to the part number as well as the Hi Res Pics which show this Unit from all different angles and make sure it satisfies your needs. The Unit was tested and works perfectly.  The suction is strong and putting the palm of you hand on the inlet side proves the fact. This is an OEM Unit made by Pierburg of Germany. You take your chances when installing after market Units and you run the risk of failing emissions. The BMW part numbers - 11.72 1 432 718 - for this Pump are shown in one of the Pics so please make sure that the Unit you are replacing has either the same part number or is otherwise compatible. As an added Bonus you get the Mounting Bracket and a pig-tailed Input Connector. The Connector often goes bad. There are Three Cushions used to attach the Bracket to the Pump but only one is good and two will definitely need to be replaced. Refer to the Pics which show this Item in considerable detail from several angles and make sure it meets your needs. You are Guaranteed satisfaction and the Pump comes with an unconditional 14 day return policy. If dissatisfied just return it at your expense and your purchase price will be refunded. New this part costs 400 dollars so here you can get one at 80+ per cent off.