It is a nipple type "Standard (round hole)" for the baby bottle dedicated to Doctor Betta.
The size of the inhalation hole is suitable for newborn babies.
Made of durable and odorless silicone rubber.
There are also cross-cut type replacement parts available.

[Precautions for handling] After use, wash and disinfect by boiling for 3 to 5 minutes. Do not expose to direct sunlight.