It is designed to provide greater immobilisation than a soft cervical collar, due to its rigid, two-piece construction. The front part has chin support while the rear part supports the back of the neck. Adjustable Velcro closures facilitate securing the collar around the patient. Its EVA foam design with holes supports ventilation and comfort during use. GSTC provides Philadelphia Collar products in different sizes to assist healthcare providers in selecting a proper fit. GSTC is also an experienced manufacturer and exporter of orthopaedic and cervical aids. 

For more details - https://www.gstc.com/product/philadelphia-collar/