Herm Sprenger Bow Balance Stirrup Irons

Herm Sprenger Bow Balance Stirrup Irons feature Sprenger's famous System 4 technology, allowing immediate release of the foot in emergencies. This new "bow" form provides a great fit and improved leg position. Shock-absorbing wide tread with two densities of rubber improves grip and balance. Four direction flex eases impact on the rider's cartilage and ligaments. Sprenger quality and innovation!

[@Miss-Laine]

What’s the difference between those and Herm Sprenger System 4 Stirrup Irons? Thanks