Frequently Asked Questions

Here are some of the most commonly asked questions about our fetal dopplers. Don’t forget, you can always reach out to our friendly staff via the live chat window or emails if you have any questions or concerns.

To ensure maximum comfort and efficiency, it’s crucial to find the right size breast shield. Our default size is 24mm, which fits 95% of mothers. However, if you measure smaller than 24mm, we offer flange inserts in three sizes (17mm, 19mm, and 21mm) that can easily snap into our 24mm flanges and containers. Our Breast Shields are sized based on the width of the base of your nipple before a pumping session.


To determine the appropriate size, use a ruler to measure the width of the base of your nipple.


The following Breast Shield sizes are recommended based on the base of your nipple width:


24mm breast shield for base of nipple width between approximately 18mm and 21mm

21mm breast shield for base of nipple width between approximately 16mm and 18mm

19mm breast shield for base of nipple width between approximately 14mm and 16mm

17mm breast shield for base of nipple width between approximately 12mm and 14mm.

Each cup holds 180ml / 6oz of milk.

The Fetaliz 4.0 wearable breast pump offers three different modes to choose from: pumping mode, massage mode, and mixed mode. Additionally, it provides 9 different intensity levels to ensure maximum comfort and efficiency for each individual user.

For optimal performance, it is recommended to wear a supportive and well-fitted bra to secure the Fetaliz 4.0 wearable breast pump in place. The breast pump should be pressed firmly against the breast without any gaps. It is suggested to wear a full-coverage nursing bra that is stretchy and has a flap.

The Fetaliz 4.0 Wearable Breast Pump comes with two duckbill valves included in the package, and typically, each valve can last for 3-6 months. We offer replacement duckbill valves when it’s time to replace them. You can click here to order the replacements.

The pump parts are made of either food-grade PP material or food-grade silicone, making them free of lead, BPA/BPS, PVC, and phthalates.

All parts, except the main pump unit, are washable. They are dishwasher-safe so you can simply clean them with your dishwasher. Clean washable components

1. Rinse and wash by hand, use an exclusive wash basin for your baby feeding items.

2. Rinse or wash these parts with cold and clear drinking-level water (approx.20°C/68°F), or with warm and soapy water (approx. 30°C/86°F).

3. Use the washing agent without artificial fragrances or coloring.

4. Check carefully to check whether there is any contamination. If it does, please repeat the clean process as above again until there is no contamination.

5. After washing or rinsing, air dry these parts on a clean and unused towel, paper towel, or cloth.


Sterilize washable components

1. Boil the parts in water for at least 5 minutes. Please don’t use tap water.

2. After disinfection, air dry these parts on a clean and unused towel, paper towel, or cloth.

3. When the parts are dry, store them in a clean storage bag and in a clean environment.

4. Please don’t use a steamer or a microwave sterilizer to disinfect these parts, because the high temperature may cause deformation of them. All ultraviolet products are not recommended to be used to sterile this product.



1. Please always disinfect in accordance with the instruction in this manual.

2. Before assembly, all the parts must be completely dry.

3. Do not store any part which is not dry in an airtight container.

Fetaliz 4.0 provides a maximum suction level of 280 mmHg, a top-in-class suction level for a personal-grade pump that offers a gentle and steady suction and does not compress the breast tissue and hinder milk flow.

Circle design and easy-to-stick silicone makes Fetaliz an ideal tool for milk leakage avoidance.

Fetaliz operates with minimal noise, producing a faint sound below 45 decibels. This makes it a discreet option for use in both professional and personal settings, allowing you to pump without drawing unnecessary attention.

For your peace of mind, the Fetaliz 4.0 wearable breast pump comes with a 12 months warranty. We also have a Customer Care Team who are ready and waiting to help you through your pumping journey.

Firstly, please follow the attached self-check video and make sure all parts are put together correctly. As the pumps will not work if the parts are not in the place they are supposed to be. If all parts are correctly installed, then it comes down to the flange sizes. Remember to choose the right size for you before purchasing. Testing the suction of your breast pump is a simple process that can be done using the following steps, along with the attached video example:


a. Turn on the pump and switch it to suction mode (indicated by a water drop icon on the control panel). Set the gear to the highest level (9 out of 9).

b. Place the pump head against your arm and test the suction.

c. If the pump is working properly, you should feel it and see light marks on your arm, as demonstrated in the attached video. Suction Strength: The Fetaliz 4.0 features three modes – pumping, massage, and mix mode, with 9 suction levels to imitate a baby’s natural suckling pattern. If the suction feels too strong, kindly reduce the gear. Most moms find gear 4 or 5 sufficient for their needs. We hope this information helps and we encourage you to reach out to us if you have any further concerns or questions.