Blast from the past- Elecro-Harmonix Phase Shifter v1

I was going through some boxes, and found an Electro Harmonix Small Stone Phase Shifter that's over 30 years old. A pic of it can be found here:

http://filters.muziq.be/model/eh/badstone

There's a female hole for a power supply. I'm trying to figure out if it takes a battery, but can't seem to get the casing apart. I'll take another look at the link above to see what kind of PS it takes. Would be cool to do a review on an ancient box like this.