Stirrup leathers in English riding are attached to the saddle and extend downwards, but not all stirrup leathers can be combined with all saddles.
The stirrup leathers on monoblate saddles are designed a little differently from those on other saddles. You must use stirrup leathers that are specially designed for this type of attachment. In addition, one-piece stirrup leathers feature special protection to protect the saddle from damage, which you don't need with wraparound stirrup leathers designed for double flap saddles.
The stirrups themselves, on the other hand, can be combined with all stirrup leathers, you just have to make sure that you attach your stirrups properly to the straps so that you can rely on them in any situation.