Wear your Fitbit Charge with your mechanical watch | Smartlet
Wear your Fitbit Charge
and your mechanical watch
at the same time
Fitbit Charge 5 and 6 pack exceptional health density into a slim form factor - ECG, EDA stress sensor, SpO2, continuous heart rate, sleep staging, GPS. Your Tudor Black Bay or Seiko Presage belongs to a world of mechanical precision. Smartlet One clips your Fitbit Charge onto any mechanical watch strap, letting both coexist on the same wrist. Fitbit Charge 5 and 6 use an 18mm band attachment, which is natively compatible with Smartlet. No adapter required. All Charge sensors maintain skin contact for accurate health data.
How it works
Classic, Shadow, or Titanium. Match your mechanical watch case material and aesthetic. No tools required at this stage.
Attach the Smartlet adapter to your watch lugs. The spring-loaded mechanism locks in place with zero metal-to-metal case contact. Fully reversible in seconds.
Attach the Smartlet adapter to your Fitbit Charge. It locks securely. Both watches sit on the same wrist. All sensors remain in contact with your skin.
Fitbit Charge models supported
| Series | Smartlet compatible | Lug width | Release year | Case size |
|---|---|---|---|---|
| Charge 5 | Compatible | 20mm (with adapter) | 2021 | 36.8mm |
| Charge 6 | Compatible | 20mm (with adapter) | 2023 | 37.0mm |
Mechanical watches worn with Fitbit Charge
Other smartwatches
Frequently asked
Can I wear a Fitbit Charge and a mechanical watch at the same time?
Yes. Smartlet One is a modular adapter that clips onto any mechanical watch via an 18mm to 24mm adapter, allowing you to simultaneously wear your Fitbit Charge on the same wrist. Both watches operate independently. No modification required.
Which Fitbit Charge models are compatible with Smartlet?
Fitbit Charge 5 and Charge 6 are both compatible with Smartlet. Both models use an 18mm band attachment, which is natively supported. No adapter required.
Will Fitbit Charge sensors still work when attached to Smartlet?
Yes. All Fitbit Charge sensors including ECG, EDA stress sensor, SpO2, and optical heart rate maintain full wrist contact via Smartlet. Google's Fitbit health platform including sleep staging and stress management continues to function normally.
Does Smartlet work with Fitbit Charge 6?
Yes. The Fitbit Charge 6 uses an 18mm band attachment, which is natively compatible with Smartlet. No adapter required. All sensors including ECG and EDA stress remain operational.