Features：
1. Four size in one combination, very convenient to adjust size
2. 4 standard adult neck braces with 16 precise adjustment points
that can be set according to the specific requirements of the user
3. Compatible with airway opening for monitoring carotid pulse and
airway intubation
4. Open rear design for palpation and ventilation
5. A unique locking lock ensures stability and symmetry of the
plunger