ESS E-Tronic Tuner for S55. I took it off my F80 before selling it a year ago. It was installed by the prior owner of my car so I just have the part. No box or papers. Was functioning fine when taken off the car. Been sitting in my closet since.
Sold.
More info:
https://esstuning.com/ess-news/s55-e...bmw-f8x-m3-m4/