a, Boss PH-2 Super Phaser

Rate
controls the speed/rate of the LFO wave that controls the effect
Depth
controls the depth/amplitude of the modulation (the size of the range in which the effect sweeps).
Res
sets the amount of effected signal fed back into the effect (for a stronger effect)
Mode I/II
switches between 2 modes, mode I is more mellow than mode II.
a true classic in the Boss line, if you missed one on their long run (now discontinued), this one is truly in collector’s condition