45 degree Buckle RB 80 includes one replacement pair of 45° buckles and mounting hardware for Rollerblade RB 110, Cruiser and RB 80 3WD skates, located in the instep under the cuff and above the laces.
The set includes both left and right
These type of buckles or straps all have only one hole on both sides. They only vary in length. As long as the length will work, you can use any brand buckle on any brand boot.
Buckles that are mounted like this are called SBM2 which stands for Standard Buckle Mount with a total of 2 bolts.