This 90 degree boss adaptor is designed to allow the Redback Mini catalytic converter to be fitted in confined areas. Designed to screw into an M18 x 1.5 lambda sensor port on the exhaust system.Dimensions - 45mm Long x 30mm DiameterPLEASE BE AWARE: Sports cats can NOT legally be installed on a vehicle for use on a public road that was manufactured after 1st March 2001 unless type ECE 103R approved. Fitting a De Cat / Cat Bypass or GPF delete / bypass to a vehicle that is to be used on UK roads will cause the vehicle to fail the MOT emissions test, therefore rendering it unroadworthy and illegal to be used on the road.Generally speaking, replacing your stock cat will also require a remap, as the ECU will be getting different readings from the Lambda sensors in the exhaust which will probably read as an error. Normally an upgraded cat is an essential part of the highest-performing upgrade packages.