Do lambda spacers work???

[ChristopherLembra]

Hi, I want to remove my primary cats (then exhaust is full straight pipe) but I dont want to have CEL. I did some research and I could get some lambda spacers. For the second lambda sensors. Now I texted my mechanic and he said they wouldnt work, that he has tried already.
Why wouldnt they work?? I think the ratings would be bad and there would be many videos about why they are so bad.

 

[Stocious]

Why would you want to retract sensor from pipe, off top of my head it’d take longer to heat up, seems like some kinds gimmicky thing