This crucifix has been blessed with a exorcism blessing specific to the embedded St Benedict Medal.   It's used for protection of a person or location/item. It's also commonly used in house blessings, deliverance and exorcisms.
 
On the back of the medal, the cross is dominant. On the arms of the cross are the initial letters of a Latin prayer: Crux sacra sit mihi lux! Nunquam draco sit mihi dux! (May the holy cross be my light! May the dragon never be my guide!).
 
Above the cross is the word pax (peace), that has been a Benedictine motto for centuries. Around the margin of the back of the medal, the letters V R S N S M V – S M Q L I V B are the initial letters of a Latin prayer of exorcism against Satan: Vade retro Satana! Nunquam suade mihi vana! Sunt mala quae libas. Ipse venena bibas! (Begone Satan! Never tempt me with your vanities! What you offer me is evil. Drink the poison yourself!)
 
The Saint Benedict Medal is a Christian sacramental medal containing symbols and text related to the life of Saint Benedict of Nursia, used by Roman Catholics, as well as Anglicans, Lutherans, Methodists and the Western Orthodox, in the Benedictine Christian tradition. The medal is one of the oldest and most honored medals used by Christians and due to the belief in its power against evil is also known as the "devil-chasing medal". 
 
As early as the 11th century, it may have initially had the form of Saint Benedict's cross, and was used by Pope Leo IX. In widespread use after its formal approval by Pope Benedict XIV in the 18th century, the medal is used to ward off spiritual and physical dangers, especially those related to evil, poison, and temptation.