The Berkeley book, which I had my hands on once, doesn't say any more about self-circumcision kits and anti-circumcision rings
than just to mention them and allege that they were offered to the public. There is one patented device with the title "anti-
circumcision ring" Twachtnman, U.S. patent 2,538,136 patented in 1951. It appears to be a ring made of sponge rubber,
slightly oval shaped and thicker on one side than on the other. It is to fit behind the corona with the thicker portion on top
of the penis, so as to keep the foreskin retracted at all times and thus secure some of the benefits of circumcision without
resort to surgery.
The Berkeley book is, to my thinking, weird and of little interest to would-be foreskin retractors except for the one passage
which I quote below
"The [Korean] war finally ended, and the fifties became the golden era
for the all-American boy -- a boy who was cleancut of hair, of jaw,
and of penis. Dr. Spock advocated that parents have their son
circumcised because 'it makes him feel regular.' Many ethnic minorities,
missed by the original circumcision bandwagon, now started sending
their little squires to school with unmuzzled acorns. Circumcision
tools became big business for the surgical supply companies, and new
gadgets flooded the market. 'Self-circumcision' kits were advertised,
as were anti-circumcision rings. Advertisements promised that the
rings would provide all the 'benefits' of circumcision without the
pain of surgery.
"These rings were advertised for teenage boys to wear much as they
would wear braces on their teeth. The ring fit on the shaft of the
penis, and trapped the foreskin behind the corona of the glans. The
theory was that the glans would permanently expand once the
foreskin stopped restricting it, and the expanded glans would thus
trap the foreskin behind it forever.
"One farm-raised man described his experience:
'My new stepfather fit the rings on me when I was twelve years old.
He told me all the boys had to wear them. They must have worked
because I only wore them for about a year and I've never been able
to get my foreskin to go up over the glans since, unless I tug at it.
My older brother wasn't so lucky. He was sixteen when he got fitted
and I guess it was too late. We did everything we could think of
to make his cockhead get fatter, but every time he took off his
rings his ole foreskin would just roll back over everything. He
wore the rings right up to the time he joined the Marines. They
solved his problem in Korea when they circumcised him clean off.'
"American men who still had prepuces became a distinct minority. They
faced humiliation in public showers and the trauma of being different.
Like most minority groups, uncircumcised boys developed guilt complexes
which, in their case, often became erotic circumcision fantasies.
Emergency wards treated countless teenagers who messed up a self-
circumcision attempt. One urologist estimated that such attempts
were the second most frequent cause of boys ending up in his emergency
care, the first being the placement of objects inside their urethra."
I have no idea where you would look to find advertisements for the devices,
if such actually existed.