Which of these is an example of an apparatus used in Pilates?

The Reformer is an essential piece of apparatus in the Pilates method. It is a versatile piece of equipment designed to provide resistance and support for various exercises, allowing practitioners to enhance their strength, flexibility, and alignment. The Reformer works by utilizing springs that can be adjusted to create different levels of resistance, making it suitable for individuals at varying skill levels and physical capabilities.

Unlike the other options listed, the Reformer is specifically developed for Pilates practice and embodies the principles of the method, including control, precision, and breath. This uniqueness allows users to perform a wide range of movements targeting different muscle groups while focusing on core stability and body awareness. The use of the Reformer in Pilates is fundamental to progressing in the practice and achieving a balanced, strong body.