Introducing the Acavallo Arena AluPro Stirrups. The bow of these stirrups is crafted from strong aluminum, while the unique stress-actuated locking and release mechanism is made of a special polyamide material - offering increased comfort in the saddle. Features include a stress-actuated locking and release mechanism, stainless steel tread, shock absorbing properties, and great support for orthopedic problems, offering support for foot bottoms, ankles, knees and hips. The caliper bracket is made of aluminum, while the opening arm and caliper are made of polyamide. The tread is made of stainless steel. The "AluPro" model performs the same functions as the Arena "HiFlex" model but uses different materials. The stirrup has a unique stress-actuated locking and unlocking mechanism located between the lower end of the outer bracket's pivot arm and the footplate/sole. It offers easy and reliable re-engagement of the stirrup lock/unlock mechanism with a single click, once triggered. Due to its flexible polymer design and construction, the stirrup provides a less rigid and much more comfortable feel than conventional products. The arch of the stirrup and the foot support effectively absorb and compensate for sudden and long-term impacts from the rider's weight from above, e.g. when saddling up, jumping or riding.