Mazda MX-5 NA/NB Radium Catch Can Kit (90-05)Radium Catch Can Kit, 90 05 Mazda MX 5 An oil catch can is essential on a performance vehicle to protect the engine from elevated levels of crankcase blow by accumulated from high performance driving. Excess oil saturated air circulating back into the air intake stream can lead to degraded performance. Radium Engineering catch cans feature large 10AN ORB ports, a 4AN ORB drain port, 2 step oil separation baffling, and an O ring sealed dipstick.