Inserters are designed to stretch the circular spring of a contraceptive diaphragm into a long oval and to furnish a handle with which it may be inserted into the vagina and guided beyond the cervix. To some users they have the esthetic appeal that they minimize digital contatc with jelly or cream, or genitals.
Robert L. Dickinson
Techniques of Contraception Control
Jour. Am. Med. Assoc., Vol. 123, 1943