The Hard Cervical Collar is a similar design to the soft collars, but are constructed out of plexiglass. They are easily applied and are easy to keep clean, an advantage over the plastic collar. This type of collar is also supplied in different sizes to fit the patient. These collars restrict motion in flexion and extension. They not only support the chin but also the occiput, reducing active extension, especially in the end phase. A drawback of the Hard Cervical Collar is that they potentially can cause venous outflow obstruction, which may elevate intracranial pressure. If there is a clear evidence of an increased intracranial pressure, the collar should be removed or re-positioned.