The material used to make nipples.
Silicone: Often transparent or milky white, silicone is known for its durability and longer lifespan compared to rubber bottle nipples. It can withstand temperatures of up to 120°C and has a usage lifespan of approximately 6 months with proper care. However, this lifespan may be reduced to 1.5 to 2 months if exposed to frequent high temperatures.
Rubber: Natural rubber bottle nipples are typically yellowish-brown in color. They are softer than silicone bottle nipples. They can withstand temperatures of up to 100°C and have a usage lifespan of about 3 months. However, if exposed to frequent high temperatures, their lifespan may be less than 1 month.