Rollerblade Maxxum XT Middle Buckles and straps match those found on Maxxum XT and Maxxum 125 Skates, but they use standard mounting (SMB) to be compatible with other brands and models using this same common mounting method. These straps are also commonly referred to as 45-degree straps, power straps, or ankle buckles. 
 
Standard Middle Buckles (SMB). Two-point mount buckles or straps that mount at one point on each side.  SMB buckles and straps are compatible across different brands and models using this same mounting method.