grp synthesizer stereo out module price : $379.99

four channel output mixer
ins 1,4 freely pannable l-r
ins 2,3 hard pannedl full l-r
stereo main out w sep levels and vu-meters.
two phones out with adjustable volume

specifications:
panel width: 16 hp
+12v = 90ma
-12v = 80ma
+5v = 0ma

download the user manual here.