It looks like you're referring to Avent Natural Nipple size 0+ (1 piece), which is likely a Philips Avent baby product.

Philips Avent Natural Nipple (Size 0+)

Size 0+: Designed for newborns (0+ months), with a slow flow suitable for breastfed babies.

Natural Shape: Mimics the breast for easier switching between breastfeeding and bottle feeding.

Material: Made from soft, flexible silicone for comfort.

Compatibility: Fits Philips Avent Natural bottles (classic and anti-colic).

Includes: Usually sold as a single nipple (1 piece) or in multipacks.