The M350 allows for a wide range of motions including forward and lateral flexion, extension and rotation. Includes head harness only. 

The M350 has four attachment points. The Head Harness should fit snugly around head. Choose a smaller size if in-between sizes. Tubing sold separately. Interchangeable.

X-Small: 18.5-19.6in (46.9-49.8cm)
Small: 19.6-21.2in (49.8-53.8cm)
Medium: 21.2-22.4in (53.8-56.9cm)
Large: 22.4-24.0in (56.9-60.9cm)
X-Large: 24.0-25.1in (60.9-63.8cm)