As the Holy See explained on August 29, 1844 and June 3, 1925, it is permissible to place the Scapular in protective cases. However, the ribbons or cords (not chains) that connect the two parts of the Scapular must be attached to the parts of the Scapular themselves, and not to the cases.
It’s pretty, but I believe to be legitimate a scapular has to be made from wool. At least for the Sabbatine Privilege.
@Angela M Hancock - You're right. The scapular needs to be made out of wool. A scapular medal (obverse OLO Mt. Carmel, reverse Sacred Heart) is an acceptable substitute if there's a serious enough reason.
Prefer the brown (but they get used quick...)
The scapular medal is permitted in certain cases but if one can obtain and wear the brown scapular in it pure original wool form, that would be most in line with Our Lady's promise.