I had to get my DII inspected and did not have the funds for new cat on passenger side. PO had driven with 2 major misfires and ruined the cat.
For a temp fix and inspection, I ordered the Blox Racing BXFL-00108 Check Engine Light Eliminator Adapter from Amazon and paid 8.00, removed the O2 sensor, screwed this in and reinstalled the sensor. No more check engine light or code.
I will replace the cat when I can, but for now, I passed inspection and am legal(so to speak)
I know if you are planning on running headers, this or the weld-on type would be the way to go. FYI the thread size is 18mmx1.50.

 

I'm surprised one that short worked for you. Your cat must still be semi-functional. I tried that length without cats and it threw a code. I went with this longer 90 degree type and no codes.