Masata BMW N55 Lambda Spacer Fooler O2 Oxygen Sensor BossThe N55 spacer is designed to move the lambda sensor after the catalytic converter away from the flow of exhaust gases when a car has a sports cat or Decat to keep the engine light off. It can also be used in some applications to move the lambda sensor away if its touching something and space is there to fit and use this. PRODUCT SPECIFICATION Height when fitted: 45mm, Total height without fitting: 50mm, Length: 45mm, M18 x 1. 5mm thread. Manufactured