Wear any smartwatch with any mechanical watch

Wear any smartwatch with any mechanical watch

Smartlet is a modular adapter that clips any smartwatch onto any mechanical watch strap. Compatible with all standard lug widths from 18mm to 24mm. All sensors remain fully operational. No tools, no modifications, fully reversible.
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Compatibility

Wear any smartwatch with any mechanical watch

Smartlet is a modular adapter that clips any smartwatch onto any mechanical watch strap. Compatible with all standard lug widths from 18mm to 24mm. All sensors remain fully operational. No tools, no modifications, fully reversible.
14+
Brands with full guides
100+
Models compatible
18-24mm
Native lug range
0
Tools required

Choose your smartwatch

Apple
Apple Watch
Series 0 to 11 - SE - Ultra - Ultra 3
ECG, SpO2, heart rate, skin temperature, crash detection
20mm / 22mmView guide →
Samsung
Galaxy Watch
Watch 4 - 5 - 6 - 7 - Ultra
ECG, BIA body composition, SpO2, heart rate
20mm / 22mmView guide →
Garmin
Forerunner
FR 255 - 265 - 955 - 965
Pulse Ox, heart rate, HRV, training readiness
20mm / 22mmView guide →
Polar
Vantage
Vantage M2 - V2 - V3
10-LED heart rate, HRV, SpO2, orthostatic test
22mmView guide →
Google
Pixel Watch
Pixel Watch 1 - 2 - 3 (41mm & 45mm)
ECG, SpO2, heart rate, skin temperature, Fitbit
20mm / 22mm (with adapter)View guide →
Huawei
Watch GT
GT 3 - GT 4 - GT 5
ECG, SpO2, TruSeen heart rate, skin temperature
20mm / 22mmView guide →
Fitbit
Charge
Charge 5 - Charge 6
ECG, EDA stress, SpO2, sleep staging
20mm (with adapter)View guide →
Fitbit
Fitbit Air
Screenless tracker (2026) - pre-order
Optical HR, SpO2, skin temperature, AFib, HRV
Proprietary (adapter incl.)View guide →
Whoop
Whoop 5.0 / MG
Whoop 5.0 - Whoop MG
HRV, heart rate, SpO2, respiratory rate, skin temp
20mm (with adapter)View guide →
Garmin
Venu
Venu 2 - 2 Plus - 3 - Sq 2
SpO2, heart rate, HRV, body battery, sleep
18mm / 20mm / 22mmView guide →
Withings
ScanWatch
ScanWatch - Light - 2 - Nova
ECG, AFib detection, SpO2, breathing disturbances
18mm / 20mmView guide →
Coros
Coros
Apex 2 - Pace 3 - Vertix 2
Heart rate, SpO2, HRV, EvoLab, multi-band GPS
20mm / 22mmView guide →
Suunto
Suunto
9 - Race - Vertical
Heart rate, SpO2, HRV, barometric altimeter
20mm / 22mm / 24mmView guide →
Panther
Panther Eclipse
Eclipse
18mmView guide →

All compatible smartwatches

Amazfit
GTR 4, GTS 4, Falcon, T-Rex Ultra, Balance, Cheetah Pro
20mm / 22mm
Garmin Instinct
Instinct 2, Instinct 2X Solar, Instinct Crossover
22mm
Garmin Epix
Epix Gen 2, Epix Pro 42 / 47 / 51mm
20mm / 22mm
Fossil
Gen 6, Gen 6 Wellness, Hybrid HR
18mm / 20mm / 22mm
Mobvoi TicWatch
Pro 5 GPS, Pro 3 Ultra, E3
22mm
Xiaomi
Watch S3, Watch 2 Pro, Watch Color 2
22mm
OnePlus Watch
Watch 2, Watch 2R
22mm
Polar Grit
Grit X2 Pro, Grit X
22mm
Polar Ignite
Ignite 3, Ignite 2
20mm
Polar Pacer
Pacer, Pacer Pro
20mm / 22mm
Huawei Band
Band 8, Band 9
18mm
Honor Watch
Watch 4 Pro, Watch GS 3
20mm / 22mm
Oppo Watch
Watch 4 Pro, Watch X
22mm
Realme Watch
Watch 3 Pro, Watch S Pro
22mm
TAG Heuer Connected
Calibre E4 45mm, Golf Edition
22mm
Montblanc Summit
Summit 3, Summit Lite
22mm
Tissot T-Touch
T-Touch Connect Solar
21mm
Kospet Tank
Tank T3 Ultra, Tank Pro 2
24mm
Casio G-Shock
GBD-H2000, DW-H5600, GM-B2100
20mm
Oura Ring
Ring 4, Ring 3
N/A - ring form factor
Panther
Eclipse
18mm

26mm variants: not compatible

51mm (26mm lug): not compatible

26mm variant: not compatible

Proprietary band on most models, conversion adapter required

Not wrist-based, not compatible with Smartlet

Explore further

Browse all
Watch Brands
27 brands covered→
Browse all
Iconic Models
50+ iconic models→

Step by step

Replace your strap
01

Replace your strap

Smartlet replaces your mechanical watch strap via the standard spring-bar system. Classic, Shadow, or Titanium. No tools required.

Connect your wearable
02

Connect your wearable

Smartlet uses a dedicated adapter or native lug pins depending on your smartwatch. The connector snaps onto the Smartlet module. Zero modification to the mechanical watch.

Wear both simultaneously
03

Wear both simultaneously

Both watches sit on the same wrist. All smartwatch sensors maintain direct skin contact and operate normally.

Questions

Frequently asked questions

  • What lug widths does Smartlet support?
    Smartlet natively accommodates any smartwatch band attachment from 18mm to 24mm, with no adapter required. This covers the vast majority of the market: Apple Watch (20mm/22mm), Samsung Galaxy Watch (20mm/22mm), Garmin Forerunner, Venu, Polar, Withings ScanWatch (18mm to 22mm), Amazfit, Fossil, TicWatch, Xiaomi, OnePlus, Honor, Oppo (22mm). Models with 26mm lugs are not compatible with Smartlet. This includes the Garmin Instinct 2X, Garmin Epix Pro 51mm, Coros Vertix, and Kospet Tank. Some smartwatches use proprietary band systems (Google Pixel Watch, Whoop, certain Casio G-Shock): a conversion adapter may be required in those cases. Smartlet does not sell these adapters directly.
  • Do smartwatch sensors still work when attached to Smartlet?
    Yes. Smartlet replaces your mechanical watch strap via the standard spring-bar system and positions your smartwatch against the wrist, maintaining direct skin contact for all optical sensors. ECG, SpO2, heart rate, skin temperature, and motion sensors all continue to function normally. GPS, altimeter, and barometer are hardware-based and completely unaffected.
  • Does Smartlet work with all mechanical watches?
    Smartlet works with any mechanical, automatic, or quartz watch with a standard lug width between 18mm and 24mm. This covers the vast majority of men's and unisex watches including Rolex, Omega, Tudor, TAG Heuer, Breitling, IWC, Seiko, and hundreds of other brands.
  • Is Smartlet reversible?
    Yes. Smartlet attaches and detaches in seconds with no tools required. Your mechanical watch strap, case, and lugs are not modified in any way. The spring-loaded mechanism makes zero metal-to-metal contact with the watch case.