Don't you mean Full Analogue Tape Saturation and Optimiser?
EMPIRICAL LABS EL7 FATSO modelled under license by Universal Audio's Digital arm deserves another rave. Having owned this system for over 6 months there is not a recording, mix or master that hasn't been through the FATSO. At the end of my chain for recording, across the Drum Buss for wonderful parallel compression, or as a replacement for my beloved SONY APR 5003 Tape machine during the mastering process - this device is as much a classic as the "Distressor" also from E Labs. If you haven't heard them or checked them out maybe this rave will entice you to do so. A wonderful engineer and mentor of mine, Mick Wordley from Mixmasters in SA said to me when he heard I was purchasing one - "the FATSO? Permanently chained across my mix!"