I don’t even know what they are. However I have seen them.
Scapular: An ecclesiastical vestment commonly worn by regular clergy. It consists of a long piece of cloth with a hole for the wearer’s head that, when worn, stretches down the front and back of the body and reaches down to near the feet…
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From what I recall…
A scapular is a piece of clothing. They did not become popular as a devotional item until Our Lady was seen (or claimed to be seen) by saint Simon Stock of Aylesford, England. Now this was very fortuitous for the Carmelites, because they had previously been monastics in the Holy Land who fled when the crusader states collapsed. They were hurting in a big way.
The Carmelite arrival in Europe was none too well accepted by the local European population in most areas, who did not generally like these “foreign” type rootless priests and monks. They also had a charter issued by the Latin patriarch of Jerusalem, it did not give them the right to settle and work in diocese outside of the Patriarchal territory of Jerusalem and many local bishops and pastors in Europe objected to their presence, which was something akin to squatting. Carmelites (at that time) had very little property to speak of, no regular means of support and were in danger of dying out.
The news of this apparition changed all of that. Apparently Our Lady referred to the habit of the Carmelites and that they can be certain that anyone wearing it at time of death was assured of salvation, perhaps she was intending to steel the resolve of the discouraged and weary group.
This type of assurance…the guarantee of being saved…always attracts people, even today. Naturally, membership in the order shot up dramatically in the thirteenth century, the order experienced explosive growth and some non-religious individuals took to wearing the scapular (the article of clothing) under their street clothing as protection against their damnation in case of sudden death. I am not certain that this is what Our Lady actually intended, or even if that is St Simon Stock’s original understanding of his vision, but non-Carmelites were wearing the habit under their streetclothes nonetheless.
This is what the enrollment is all about, making one a “type” of Carmelite while not actually being part of the community. It has to some minds the effect of qualfying laypersons for the promise of salvation.
Eventually, lay styles of clothing have changed and the scapular was uncomfortable and not easy to conceal, so it became greatly reduced in size. Now it is two small patches of wool joined by slender ribbons or cords. It is as small as one can imagine for a piece of clothing. One might see why changing it to a more durable and attractive medal defeats the purpose of Our Lady calling upon people to take up the Carmelite habit.
Since that time, various communities and missions have raised money by promoting mini-scapulars and medals. The group issuing or producing it is widely identifiable and sometimes can count on some free will donations coming in with the request for a medal or scapular, or requests for enrollment.
I am not familiar with all of the differences with these new ones, and I doubt there have been separate apparitions claimed for every one. I think that the varieties have been formally approved by different Popes on behalf of different groups.
Michael
) Perhaps they are not as familiar sacramentals because, by their very nature, they are so private and hidden? I don’t know. But they should definitely stick around for awhile. 
However, the Sabbatine Privilige can’t be received (and some of the indulgences of the Scapular?) if one wears a medal instead, unless it’s for a serious reason (check with confessor…vanity doesn’t count.) Just an FYI.