Breast Pump Accessories – Flange & Duckbill Valves for S18/S21

Replacement Breast Pump Accessories for S18 & S21 Wearable Electric Pumps

Keep your pumping routine running smoothly with these high-quality replacement accessories designed specifically for S18 and S21 wearable electric breast pumps. Whether you need a new flange, milk collector, silicone diaphragm, or duckbill valves, this set has everything you need to maintain optimal suction and hygiene — so you can focus on what matters most: nourishing your baby.

These accessories are personal care / maternal health products. This product is not intended to diagnose, treat, cure, or prevent any disease. These statements have not been evaluated by the Food and Drug Administration.

Why Nursing Moms Love These Accessories

• BPA-Free & Body-Safe Materials: Made from food-grade PP and soft silicone — safe for you and your baby.
• Designed for S18 & S21 Pumps: Engineered to fit perfectly and restore full suction performance.
• Multiple Options Available: Choose from 24mm Flange, 27mm Flange, Milk Collector, 24mm Set, or 27mm Set to match your exact needs.
• Durable & Long-Lasting: High-quality PP + silicone construction ensures these accessories stand up to repeated use and sterilization.
• Easy to Assemble: Snap-on design makes setup and cleanup quick and hassle-free.
• Discreet & Convenient: Compatible with wearable pumps so you can express milk at work, while traveling, or on the go.

Specifications

• Material: PP + Silicone (BPA-Free)
• Available Types: 24mm Flange | 27mm Flange | Milk Collector | 24mm Set | 27mm Set
• Silicone Diaphragm Size: Approx. 46 × 40 mm (1.81 × 1.57 in)
• Duckbill Valve Size: Approx. 11 × 26 mm (0.43 × 1.02 in)
• Compatible With: S18 & S21 Wearable Electric Breast Pumps
• Country of Origin: Made in Mainland China

What's in the Package

Depending on your selected option, your package will include:

• 1× Flange (24mm or 27mm), OR
• 1× Milk Collector, OR
• 1× Milk Collector with Silicone Diaphragm & Duckbill Valves

Note: Please allow 1–2 cm variance due to manual measurement. Slight color differences may occur due to screen resolution variations.

Expert Breastfeeding Resources

Maintaining proper pump equipment is essential for effective milk expression. Learn more about breastfeeding best practices and equipment hygiene from the CDC's Breastfeeding Guidelines.

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Frequently Asked Questions

Q: Are these breast pump accessories BPA-free and safe for my baby?

A: Yes! These accessories are made from food-grade PP and silicone materials that are completely BPA-free. They are designed to be body-safe and suitable for repeated use and sterilization, giving you peace of mind while expressing milk for your baby.

Q: Which breast pump models are compatible with these accessories?

A: These replacement parts are specifically designed for the S18 and S21 wearable electric breast pumps. Please verify your pump model before purchasing to ensure a proper fit.

Q: How do I know which flange size to choose — 24mm or 27mm?

A: The correct flange size depends on your nipple diameter. Most lactation consultants recommend measuring your nipple (not the areola) and selecting a flange that is approximately 3–4mm larger. If you are unsure, consult a lactation specialist for personalized advice.

Q: How often should I replace the duckbill valves and silicone diaphragm?

A: It is generally recommended to replace duckbill valves every 4–8 weeks or if you notice a decrease in suction, cracking, or discoloration. The silicone diaphragm should also be inspected regularly and replaced if worn. Having spare parts on hand ensures consistent pumping performance.