Wear a Smartwatch with Your Zenith | Smartlet

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.