Rubber vault cap, "Dumas Antigenture" type, by Adeline Dumas, London and Paris

A vault cap is a barrier contraceptive. It sits over the cervix and acts as a barrier to sperm entering the uterus. This is an example of a Dumas type cap, invented by Adeline Dumas. It is made of rubber manufactured in both Paris and London. Cervical caps and the slightly larger alternative, the diaphragm, must be initially fitted by a physician. This establishes the shape of the cervix and the size and type of cap required.