Wear a smartwatch with your Zenith

Wear a smartwatch with your Zenith

Smartlet One is compatible with all Zenith El Primero, Chronomaster, and Defy references using 18mm to 22mm lug widths, natively supported with no adapter. Installation uses the standard spring-bar system - no modification to the watch, fully reversible in seconds.
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Zenith compatibility

Wear a smartwatch with your Zenith

In short Smartlet One is compatible with all Zenith El Primero, Chronomaster, and Defy references using 18mm to 22mm lug widths, natively supported with no adapter. Installation uses the standard spring-bar system - no modification to the watch, fully reversible in seconds.

Zenith kept the El Primero movement alive when the quartz crisis pushed Swiss manufactures to destroy their mechanical tooling. Charles Vermot hid the parts in an attic. The El Primero beats at 36,000 vph - five beats per second - and measures to one-tenth of a second. That frequency makes it one of the most accurate mechanical chronograph movements in production. The Chronomaster carries that movement. Smartlet One attaches at the lug ends via spring bars. The column wheel, the tri-colour dial, the 400 calibre - none of it is modified.

Wear yours How it works
The problem
Choosing between health data and horological heritage every morning.
The solution
Smartlet One replaces your Zenith's strap via the standard spring-bar system and positions your smartwatch on the same wrist. Both watches run simultaneously, with no modification to the watch and full reversibility in seconds.
Brand
Zenith
Lug widths
18.0mm / 19.0mm / 20.0mm / 21.0mm / 22.0mm / 23.0mm / 24.0mm
Iconic models
1covered
Compatibility
Full range

Choose your edition

One mechanism. Three personalities.

Every Smartlet One includes the dedicated adapter for your wearable. Pick the finish that matches your style.

Smartlet One - Shadow - Smartlet

For the explorer

Smartlet One - Shadow

€399,00

4.9 (14)

Stealth. Switch in seconds, leave no trace.

  • Material SS316L steel, black PVD
  • Weight ~100g
  • Compatible with Rolex, Omega, Seiko + 100 more
Buy now
Compatibility

Zenith models supported

Zenith El Primero
19mm / 20mm / 21mm / 22mm

Other Zenith references

20 model families. Expand any group to see variants, references, and specifications.

Academy
20mm / 22mm / 23mm4 refs+
ReferenceMaterialDialLugSmartlet
ELPR-VERMOTStainless SteelTri-Color20mmCompatible
18.2210.8804/01.C713Rose GoldWhite22mmCompatible
18.2250.400/01.C630Rose GoldWhite22mmCompatible
ZeroG-2010White GoldSilver Skeleton23mmCompatible
Aéronavale
20mm1 refs+
ReferenceMaterialDialLugSmartlet
Type20-NavyStainless SteelBlack20mmCompatible
Calibre
18mm4 refs+
ReferenceMaterialDialLugSmartlet
CAL120-1953Stainless SteelSilver18mmCompatible
Cal.135-G18K Yellow GoldSilver18mmCompatible
Cal.135-1Stainless SteelSilver18mmCompatible
Cal.135-OStainless SteelSilver18mmCompatible
Captain
18mm / 19mm / 20mm10 refs+
ReferenceMaterialDialLugSmartlet
03.2110.400/01.C498Stainless SteelSilver20mmCompatible
CapDL-195718K Yellow GoldChampagne19mmCompatible
CAP-1955Stainless SteelSilver19mmCompatible
CAP-1963Stainless SteelSilver19mmCompatible
18.2120.679/01.C498Rose GoldSilver20mmCompatible
CAP-MP-1990Stainless SteelWhite19mmCompatible
CAP-TV-1973Stainless SteelBlue20mmCompatible
Cal.2532Stainless SteelSilver18mmCompatible
Cal.2532Stainless SteelBlack18mmCompatible
03.2070.4054/02.C493Stainless SteelSilver/Blue20mmCompatible
Chronograph
18mm / 19mm11 refs+
ReferenceMaterialDialLugSmartlet
146HP-1962Stainless SteelSilver19mmCompatible
146HP-1964Stainless SteelBlack19mmCompatible
Cal122-1945Stainless SteelSilver19mmCompatible
Cal143-1947Stainless SteelBlack19mmCompatible
CAL146D-1960Stainless SteelSilver19mmCompatible
CAL146HP-1964Stainless SteelGrey19mmCompatible
Cal.146D-1960Stainless SteelWhite19mmCompatible
Cal.146D-1962Stainless SteelBlack19mmCompatible
146H-1963Stainless SteelSilver19mmCompatible
TCM-1952Yellow GoldCream18mmCompatible
TC-1948Stainless SteelWhite18mmCompatible
Chronomaster
19mm / 20mm11 refs+
ReferenceMaterialDialLugSmartlet
18.3200.3600/69.C905Rose GoldTri-Color19mmCompatible
03.3200.3600/21.C903Stainless SteelBlack19mmCompatible
03.3200.3600/69.C902Stainless SteelTri-Color19mmCompatible
03.A384.400/21.C815Stainless SteelWhite/Black Panda19mmCompatible
03.A385.400/50.C385Stainless SteelGradient Brown19mmCompatible
03.A3817.400/01.C901Stainless SteelTri-Color19mmCompatible
03.3100.3600/69.M3100-BlueStainless SteelWhite/Blue20mmCompatible
18.3101.3600/69.M3100Rose GoldWhite20mmCompatible
03.3100.3600/21.M3100Stainless SteelBlack20mmCompatible
03.3100.3600/69.M3100Stainless SteelWhite20mmCompatible
18.3100.3600/69.M3100Steel/GoldWhite20mmCompatible
Chronometre
18mm1 refs+
ReferenceMaterialDialLugSmartlet
Cal.40T-1950Stainless SteelWhite18mmCompatible
Defy
18mm / 20mm / 22mm / 23mm / 24mm28 refs+
ReferenceMaterialDialLugSmartlet
97.9001.9004/80.R922TitaniumPurple Skeleton22mmCompatible
10.9000.9004/96.R941Carbon/SteelBlack Skeleton22mmCompatible
49.9000.670/77.R782Black CeramicBlack Skeleton22mmCompatible
49.9000.670/51.R793Blue CeramicBlue Skeleton22mmCompatible
95.9000.670/78.M9000TitaniumGrey22mmCompatible
A3645-1969Stainless SteelBlack20mmCompatible
18.9000.9020/78.M9000PlatinumSkeleton23mmCompatible
97.9100.9004/02.I001TitaniumBlack/Blue23mmCompatible
95.9100.9004/01.I001Brushed TitaniumGrey/Black23mmCompatible
10.9001.9004/36.R957Carbon/SteelBlack/Red23mmCompatible
95.9001.9100/78.R584TitaniumBlue Openworked22mmCompatible
Plasma-Lab1Lab-Grown SapphireClear Skeleton22mmCompatible
SQ1-1977Stainless SteelSilver20mmCompatible
SQ3-1979Stainless SteelBlue20mmCompatible
03.9300.3620/21.I001Stainless SteelBlack Sunburst22mmCompatible
03.9300.3620/51.I001Stainless SteelBlue Sunburst22mmCompatible
03.9300.3620/78.I001Stainless SteelBlack Skeleton22mmCompatible
DSS-1974Stainless SteelBlack20mmCompatible
A3646-1970Stainless SteelBlue20mmCompatible
Surf-1972Stainless SteelSilver20mmCompatible
Surf-AR-1976Stainless SteelArabic Champagne20mmCompatible
DTV-1975Stainless SteelGrey20mmCompatible
A3642Stainless SteelSilver18mmCompatible
A3645Stainless SteelBlack18mmCompatible
A3648Stainless SteelBlue20mmCompatible
A7817-1973Stainless SteelBlue/White20mmCompatible
96.0525.670/21Titanium/PvdBlack24mmCompatible
Resp-1972Stainless SteelSilver18mmCompatible
Dress
20mm2 refs+
ReferenceMaterialDialLugSmartlet
18.2010.681/01.C498Rose GoldSilver20mmCompatible
03.2010.681/21.C722Stainless SteelBlack20mmCompatible
Elite
19mm / 20mm15 refs+
ReferenceMaterialDialLugSmartlet
03.1125.680Stainless SteelBlack20mmCompatible
03.2270.4069/01.C493Stainless SteelSilver20mmCompatible
03.3100.670/02.C922Stainless SteelSilver20mmCompatible
03.1125.693Stainless SteelSilver20mmCompatible
18.1125.693Rose GoldSilver20mmCompatible
30.1120.68518K Yellow GoldWhite19mmCompatible
03.1125.685-ARStainless SteelArabic White20mmCompatible
03.3100.692/03.C923Stainless SteelBlue20mmCompatible
03.1220.4021Stainless SteelSilver Open20mmCompatible
01.1125.685Stainless SteelWhite20mmCompatible
03.3100.670/02.C922Stainless SteelWhite20mmCompatible
30.0040.68018K Yellow GoldWhite19mmCompatible
01.0040.680Stainless SteelSilver19mmCompatible
Cal.2542PCStainless SteelSilver19mmCompatible
Cal.2542PCStainless SteelBlack19mmCompatible
Grand
18mm1 refs+
ReferenceMaterialDialLugSmartlet
Cal.135-GL18K Rose GoldChampagne18mmCompatible
Officer’s
20mm2 refs+
ReferenceMaterialDialLugSmartlet
TW-1917SilverWhite Enamel20mmCompatible
TW-1918-BSilverBlack Enamel20mmCompatible
Pilot
18mm / 19mm / 20mm / 21mm / 22mm / 23mm13 refs+
ReferenceMaterialDialLugSmartlet
03.2410.4010/21.C722Stainless SteelBlack21mmCompatible
03.4000.3652/21.I001Stainless SteelBlack22mmCompatible
MoD-1950Stainless SteelBlack18mmCompatible
DH-1942Stainless SteelBlack20mmCompatible
FAF-1953Stainless SteelBlack/White19mmCompatible
MDA-1940Stainless SteelBlack20mmCompatible
29.2430.679/21.C753BronzeBrown23mmCompatible
03.2430.3000/21.C738Stainless SteelBlack23mmCompatible
11.2430.679/51.C800BronzeBlue23mmCompatible
29.2430.679/21.C753-RedBronzeRed23mmCompatible
CAF-1939Stainless SteelBlack20mmCompatible
PBA-1940Stainless SteelBlack/Ba20mmCompatible
USN-1944Stainless SteelBlack20mmCompatible
Prototype
19mm / 20mm4 refs+
ReferenceMaterialDialLugSmartlet
DEF-PROTO-1975Stainless SteelSkeleton20mmCompatible
EP-PROTO-1968Stainless SteelGrey19mmCompatible
EP5HZ-1970Stainless SteelBlack19mmCompatible
TOURB-PROTO-1998Stainless SteelWhite20mmCompatible
Rainbow
20mm6 refs+
ReferenceMaterialDialLugSmartlet
RF-YLW-1998Stainless SteelYellow/Black20mmCompatible
RF-ORG-1999Stainless SteelOrange/Black20mmCompatible
03.0470.405Stainless SteelWhite20mmCompatible
02.0480.405Stainless SteelBlack20mmCompatible
RF-FAF-1997Stainless SteelBlack20mmCompatible
RF-OPS-2000Black PvdBlack20mmCompatible
Sector
18mm2 refs+
ReferenceMaterialDialLugSmartlet
GILT-1950Stainless SteelBlack Gilt18mmCompatible
SEC-1950AStainless SteelArabic White18mmCompatible
Sporto
19mm2 refs+
ReferenceMaterialDialLugSmartlet
Cal.40T-1958Stainless SteelBlack19mmCompatible
Cal.40T-1958Stainless SteelSilver19mmCompatible
Type
19mm1 refs+
ReferenceMaterialDialLugSmartlet
Type20-CivStainless SteelCream19mmCompatible
Waterproof
18mm2 refs+
ReferenceMaterialDialLugSmartlet
Cal.106Stainless SteelWhite18mmCompatible
Cal.106Stainless SteelBlack18mmCompatible
Zenith
20mm1 refs+
ReferenceMaterialDialLugSmartlet
TI.0470.400TitaniumBlack20mmCompatible

Zenith lug widths:

18mm19mm20mm21mm22mm23mm24mm
Frequently paired

Smartwatches worn with Zenith

The most common combinations our customers wear. Find your mechanical watch and discover the right Smartlet edition.

Apple Watch
Series 0 to Ultra 3
Whoop
5.0 / MG
Garmin Forerunner
255 to 965
Samsung Galaxy Watch
Series 4 to 7
Withings ScanWatch
Light / 2 / Nova
View all brands
27 brands covered
Also compatible

Other brands

Smartlet One covers 18mm to 24mm lug widths across the finest watch brands.

ロレックス
オメガ
タグ・ホイヤー
ブライトリング
チューダー
IWC
ロンジン
セイコー
ハミルトン
グランドセイコー
Bell&Ross
ブランパン
パネライ
カルティエ
ジャガー・ルクルト
ラド
ティソ
オリス
ドクサ
Formex
Timex
ジン
ポルシェ デザイン
ミドー
イエマ
クリストファー・ワード
すべて表示
View all
Watch brand compatibility guide

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

  • Does Smartlet work with Zenith watches?
    Yes. Zenith references from 18mm to 22mm lug width are natively supported by Smartlet One.
  • Will Smartlet affect the El Primero movement?
    No. Smartlet attaches via spring-bar slots. The El Primero 400 calibre running at 36,000 vph is completely untouched.
  • Which Zenith references are compatible?
    El Primero A386, Chronomaster Original, Sport - 40 key references covered in the guide.
  • Which recent Zenith releases work with Smartlet?
    Zenith introduced a new Chronomaster Sport at Watches and Wonders 2026, presented as a first for the collection, after celebrating its 160th anniversary in 2025 with the G.F.J. powered by the revived calibre 135. As always, any reference with standard spring bars between 18mm and 24mm lug width works with Smartlet.
  • Smartletは機械式時計にダメージを与えたり、改造したりしますか?
    いいえ。Smartletは既存のバネ棒システムを使用して、標準的な時計ベルトを交換します。時計ケース、ラグ、またはダイアルに永続的な改変を加えません。このプロセスは数秒で完全に可逆的です。機械式時計は影響を受けず、元のベルトを再度取り付けることでいつでも独立して着用できます。Smartletは時計職人の精度で設計され、それが組み合わせられる時計と同じ注意深さでテストされています。