Size chart: Cervical Collar with Support

Size Type Inches Cms
S 3.0 - 3.5 7.50 - 8.75
M 3.5 - 4.0 8.75 - 10.00 
L 4.0 - 4.5 10.00 - 11.25
XL 4.5 - 5.0 11.25 - 12.50