- Length of hollow mouth oropharynx: 40, 50, 60, 70, 80, 90, 100, 110 and 120mm.

- Use by a single patient.

 Provide airway ventilation and anti-jamming features for airway management.

- Consists of a large flange, support and reinforcement of the occluding portion, and a gentle curve of the contour of the tongue, with the tubular channel down to the center of the airway to provide gas exchange, twitch catheters or other tube access.

- Hollow design principle to avoid improper twitching or intubation and injure throat soft tissue.

- Different colors can facilitate different size recognition.