This is the Brigittine rosary.
What little information there is about it tends to be confusing.
There are six decades, comprising one Our Father and ten Hail Mary’s, plus a pendant with an Additional Our Father and three Hail Mary’s.
Altogether, there are 63 Hail Mary’s, in honor of the number of years Mary is thought to have lived (The Franciscan Crown has her age as 72, however!) The total of 7 Our Fathers is said in honor of her Seven Sorrows.
There is also the Servite Devotion of the Seven Sorrows, with 7x(1+7 )beads!
The Franciscan Crown, with seven decades, is based on the seven Joys of Mary.