Oppo: Cervical Neck Collar Deluxe OP4190. Completely adjustable height to provide desired flexion or extension positioning. Vinyl-covered foam padding for patient comfort and easy cleaning. Hook and loop closure for quick, easy application and removal. Size: Measure around the circumference of the neck: 34.3-40cm Small, 40.6-46.4cm Medium, 47-52.7cm Large.