M42 Af confirm adapter

Hi all

I am thinking of getting a M42 AF confirm adapter ring, I have found a couple on ebay but one of the sellers (lily_box) feedback leaves a bit to be desired, I have also found one from seller (tagotech) who's feedback seems ok.

My questions are has anyone tried these AF rings and if so are you happy with the results, and has anyone had any dealings with either seller and were you happy with them.

I have tried searching for the subject but the search function is not working properly at the moment.
Regards

I tried one but didn't like it. Fortunately, they gave me a refund. The chip unit on the one I got stuck out too far and it caught on the camera's AF pins. I was worried it would damage the camera.

However, that was for Leica. Maybe they are not all the same.