Air / fuel mixture meter

There are a few on the market. The decent ones seem to go for a few hundred dollars depending on dual or single input and obdII access.

My question is are they necessary for tuning and worth the money. I also found one DIY that I could build for about 50 dollars.

thank you

Hi mate,
For gasoline engine tuning it's a must have,you need a good AFR tool with wideband sensor.I use one from Innovate,helped me a lot,in particular for open loop tuning.

Thank you, for your response. It makes since to me that you would want a manual true reading of the A/F at different RPM's. I just never hear anyone talking their meter. I know you can get readings from software but sometimes the actual is a little different.

Thank you