"Note here that two things must be considered regarding our good works, namely, satisfaction and merit or, in other words, their satisfactory or prayer value and their meritorious value. The satisfactory or prayer value of a good work is the good action in so far as it makes condign atonement for the punishment due to sin or obtains some new grace. The meritorious value or merit is the good action in so far as it merits grace and eternal glory. Now by this consecration of ourselves to the Blessed Virgin we give her all satisfactory and prayer value as well as the meritorious value of our good works, in other words, all the satisfactions and the merits. We give her our merits, graces and virtues, not that she might give them to others, for they are, strictly speaking, not transferable, because Jesus alone, in making himself our surety with his Father, had the power to impart his merits to us. But we give them to her that she may keep, increase and embellish them for us, as we shall explain later, and we give her our acts of atonement that she may apply them where she pleases for God's greater glory."
Source: St. Louis de Montfort from True to Devotion to Mary