Which Philips Avent Natural Nipple do I own?

Both the previous and new Philips Avent Natural Nipples are designed to look and feel like a breast, but only the new Natural Response Nipples are also designed to work like one, releasing milk only when your baby actively drinks.The Natural Response Nipple comes in 5 sizes, and they can be recognized by the following features:•    Slit on the tip of the nipple instead of a hole;•    Swirl design around the petals;•    Grey Philips Avent logo on the bottle.To check whether you have the older or new Natural Response Nipple, please refer to the illustration below.

Philips Avent Natural Nipple for Thick Feed 2 pcs, +6m - Miazone

Philips Avent 2 Pack Classic Variable Flow Nipple, 3M + – S&D Kids

Philips Avent Natural Baby Bottle Newborn Starter Gift Set

Philips Avent Natural Response Nipple Flow 4, 3m+, 4pk, SCY964/04

Philips Avent Natural Baby Bottle First Flow Nipple, 2pk, SCF657/23

Philips Avent Baby Bottle Nipples

Avent Natural Nipple Medium Flow 3M+ - Shop Nipples at H-E-B

Philips Avent 2pk Anti-colic Baby Bottle Nipple - Fast Flow : Target

Dr. Brown Bottles Vs. Philips Avent: What's The Difference & Which Baby Bottle Brand Is Better? Nipple Sizes, Anti Colic, Safety, etc. - Motherhood Community

Philips Avent Anti-Colic Baby Bottle Newborn Flow Nipple, Clear, 2pk