An anti-tamper synthetic elastomeric cap structure, of the type having a dilated external head in abutment with an apex to form a “T-cap”, includes a composite structure having, embedded in the head, an endoskeleton with external appendages that provides a cage having a circumferential projection, with respect to a penetrating body under the head that defines a band having a notching therein and disposed about the neck of a bottle to provide a pre-fracture line and a grasping appendage.
