






FPF-S1 Peak Flow Meter
The FPF-S1 peak flow meter helps families track peak expiratory flow (PEF) at home with a simple one-blow routine. A turbine airflow structure with infrared interruption sensing measures PEF from 50–900 L/min, while the device stores up to 500 records and keeps the highest value from each measurement session. Lightweight at about 108 g without batteries, it runs on two AAA batteries and supports daily morning/evening breathing trend checks for users age 5+ with adult supervision when needed.
FDA granted 510(k) clearance
FSA & HSA Payments Accepted
30-day risk-free trial
1-Year Warranty
Pairs well with

Built for PEF Measurement
Turbine + Infrared Sensing for PEF Readings.
FPF-S1 measures peak expiratory flow (PEF), the fastest airflow during a forceful exhale. A turbine airflow structure works with infrared interruption sensing to capture 50–900 L/min PEF readings, giving the device a clear measurement principle beyond a simple blow counter.

Best-Value Record
Automatically Saves Your Best PEF From Each Session.
During each power-on session, the device keeps only the highest PEF value. Users can repeat the blow three times, and FPF-S1 saves the best result as the latest record, helping reduce the guesswork of choosing which attempt to write down.

Routine Ready
Made for Daily Breathing Routines.
At about 108 g without batteries, FPF-S1 is easy to keep at home, pack for travel, or use as part of a morning and evening routine. The device stores up to 500 records and runs on two AAA batteries, so routine PEF checks do not depend on charging.
FondCircle App
Get hospital-level care from home with FondCircle’s tele-health platform and smart devices for accurate, connected health monitoring.
Data Protection
We protect your health.
We also protect your privacy.
The Fondcircle app handles your health data in accordance with HIPAA standards. Your readings stay on your device by default — sharing through CareShare is always initiated by you, and only reaches the people you choose. We do not sell your health data.
Specifications
| Model | FPF-S1 |
| Measurement parameter | PEF (Peak Expiratory Flow) |
| Measurement method | Infrared interruption with turbine / impeller airflow structure |
| Measurement range | 50-900 L/min |
| Measuring accuracy | ±10 L/min or ±10%, whichever is greater |
| Memory | Up to 500 records |
| Session record | Stores the highest PEF value from each power-on session |
| App integration | FondCircle App support for PEF records and trend review |
| Power | 2 × AAA batteries or DC 3.0V |
| Auto power-off | 3 minutes in standby |
| Prompt | Buzzer prompt |
| Display backlight | None |
| Operating environment | 5°C-40°C / 41°F-104°F 15%-90% RH 86-106 kPa |
| Storage and transportation | -25°C-55°C / -13°F-131°F 15%-93% RH 70-106 kPa |
| Dimensions | 61.49 × 88.86 × 126.70 mm |
| Weight | 108.0 ± 1.0 g without batteries |
| Service life | 3 years |
| Intended users | Children 5 years and older, adolescents, and adults Adult supervision required where needed |
Important: This device is for exhalation-only PEF monitoring. Use one mouthpiece per person and follow the user manual for contraindications, cleaning, and measurement instructions.
Download User Manual (PDF)What's in the Box
- Electronic peak flow meter × 1
- Mouthpiece assembly × 1
- Mouthpieces × 2
- AAA batteries × 2
- User manual × 1
FAQs
Please read our FAQs page to find out more.
What does the S1 peak flow meter measure?
S1 measures peak expiratory flow, or PEF. It helps you record how fast you can exhale during a forceful breath, so you can review breathing trends over time. It does not diagnose or treat respiratory conditions.
Is this a full spirometer?
No. S1 is a peak flow meter focused on PEF. It is not positioned as a professional spirometer and should not be described as measuring FEV1, FVC, or FEV6.
How do I take a measurement?
Sit or stand upright, take a deep breath, seal your lips around the mouthpiece, and blow out as hard and fast as you can for at least 1 second. For routine tracking, take three attempts and use the highest value.
Does S1 connect to the FondCircle App?
Yes. S1 supports FondCircle App integration for PEF records and trend review. App Predicted reference wording should match the final App screens before publish.
Can children use S1?
S1 is intended for users age 5 and older. Children should use it only with adult supervision and should follow the user manual carefully.
How do I clean the mouthpiece?
Use one mouthpiece per person to reduce cross-contamination risk. Clean and dry the mouthpiece according to the user manual.







