Wear your Apple Watch with your mechanical watch | Smartlet
Wear your Apple Watch
and your mechanical watch
at the same time
The Apple Watch is the world's most advanced health companion - ECG, SpO2, crash detection, sleep tracking. Your Rolex, Omega, or Tudor is an irreplaceable statement of craft and heritage. Smartlet One clips your Apple Watch onto the outer face of any mechanical watch strap via a 20mm adapter. Both watches sit on the same wrist. All Apple Watch sensors maintain full skin contact and operate normally. No compromise on either side.
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 Apple Watch. It locks securely. Both watches sit on the same wrist. All sensors remain in contact with your skin.
Apple Watch models supported
| Series | Smartlet compatible | Lug width | Release year | Case size |
|---|---|---|---|---|
| Series 0 (original) | Compatible | Full compatibility | 2015 | 38mm / 42mm |
| Series 1 | Compatible | Full compatibility | 2016 | 38mm / 42mm |
| Series 2 | Compatible | Full compatibility | 2016 | 38mm / 42mm |
| Series 3 | Compatible | Full compatibility | 2017 | 38mm / 42mm |
| Series 4 | Compatible | Full compatibility | 2018 | 40mm / 44mm |
| Series 5 | Compatible | Full compatibility | 2019 | 40mm / 44mm |
| Series 6 | Compatible | Full compatibility | 2020 | 40mm / 44mm |
| Series 7 | Compatible | Full compatibility | 2021 | 41mm / 45mm |
| Series 8 | Compatible | Full compatibility | 2022 | 41mm / 45mm |
| Series 9 | Compatible | Full compatibility | 2023 | 41mm / 45mm |
| Series 10 | Compatible | Full compatibility | 2024 | 42mm / 46mm |
| Series 11 | Compatible | Full compatibility | 2025 | 42mm / 46mm |
| SE 1st gen | Compatible | Full compatibility | 2020 | 40mm / 44mm |
| SE 2nd gen | Compatible | Full compatibility | 2022 | 40mm / 44mm |
| Ultra | Compatible | Full compatibility | 2022 | 49mm |
| Ultra 2 | Compatible | Full compatibility | 2023 | 49mm |
| Ultra 3 | Compatible | Full compatibility | 2025 | 49mm |
Mechanical watches worn with Apple Watch
Other smartwatches
Frequently asked
Can I wear a Apple Watch 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 Apple Watch on the same wrist. Both watches operate independently. No modification required.
Which Apple Watch models are compatible with Smartlet?
All Apple Watch models are compatible with Smartlet, from the original Series 0 (2015) through Series 11, SE 1st and 2nd generation, Ultra, Ultra 2, and Ultra 3. All Apple Watch models use Apple's standard band attachment system, which accommodates the Smartlet 20mm adapter.
Will Apple Watch sensors still work when attached to Smartlet?
Yes. All Apple Watch sensors including ECG, SpO2, optical heart rate, skin temperature, and the accelerometer remain fully operational. The Smartlet module positions Apple Watch on the outer face of your strap, maintaining the direct wrist contact required for accurate sensor readings.
Does Smartlet work with Apple Watch Ultra?
Yes. Apple Watch Ultra and Ultra 2 are fully compatible with Smartlet. The larger 49mm case sits securely in the module. All sensors remain operational.