Swirve
The Kustom VI was a 6 channel mono powered mixer with 7 band EQ, circa about 1974 to 1976 or after.
What was cool about it was that it was biamped - it had a 125 watt amp for the lows, a 75 watt amp for the highs and a built in active crossover at 1,000 Hz.
This worked well with Kustoms PA speakers at that time, some of which had separate Horn cabinets and bass speaker cabinets.(You can see one of these (M-15 horn cabinets)currently on e-bay.)
The Kustom VI mixer weighed 64 lbs.
As far as the value, this was after the naugahide era; I would guess $75-125 depending on condition.