The ADR Vocal Stresser F769X-R is a quirkier version of ADR's Compex F760FX compressor. A multitude of settings for both EQ and compression.
Great on drums, as evidenced by John Bonham's drum sound. Tony Visconti also used this unit a lot on the early David Bowie recordings, and William Wittman used it to great effect on Cyndi Lauper's vocals for 'Girls Just Want To Have Fun' and 'Time After Time'.