"Sacramentals are sacred signs instituted by the Church. They prepare men to receive the fruit of the Sacraments and sanctify different circumstances of life" (Catechism of the Catholic Church #1677).
"One of the most remarkable effects of sacramentals is the virtue to drive away evil spirits whose mysterious and baleful operations affect sometimes the physical activity of man. To combat this occult power the Church has recourse to exorcism, and sacramentals" (The Catholic Encyc., 1913, VXIII, p. 293).
"Another effect is the delivery of the soul from sin and the penalties thereof. Thus in the blessing of a cross the Church asks that this sacred sign may receive the heavenly blessing in order that all those who kneel before it and implore the Divine Majesty may be granted great compunction and general pardon of faults committed. This means remission of venial sins, for the Sacraments alone, with perfect contrition, possess the efficacy to remit mortal sins and to release from the penalties attached to them" (The Catholic Encyclopedia, 1913, VXIII, p. 293).
"Sacramentals may be employed to obtain temporal favors, since the Church herself blesses objects made use of in every-day life" (The Catholic Encyclopedia, 1913, VXIII, p. 293).