System Includes: 2 Silicone Wide Mouth Nipples; Tri-Flow ring, hood & sealing disk. Tri-Flow Nipple System. 1 Nipple, 3 flow rates. All ages. Fits wide mouth bottles. Rotate Nipple: Slow (0-3 mos); Medium (3-6 mos); Fast (6+ mos). Adjusts to match mother's flow for a more natural feeding experience. Less gas. Less confusion. Ring & nipple work with wide mouth bottles. Mother's breast milk at different rates - shouldn't your baby's bottle? Tri-Flow Nipple System is the only system that adjusts to match mother's flow rate. Features: Wide, soft nipple promotes natural latch-on and suckling; Sealing disk for airtight milk storage; Unique Tri-Flow design reduces gas and nipple confusion. Ideal for moms planning to switch between breast & bottle feeding. Natural choice of certified lactation consultants, moms and babies.