The ultra-small buckle extension can hardly be seen, as it is thin and covered by the leather strap. The Frederique Constant E-Strap is built on the full Horological Smartwatch Platform and its sophisticated functionality. The same MMT-365 App that accompany Horological Smartwatches is available to Frederique Constant E-Strap customers. Frederique Constant E-Straps track ACTIVITY with GET ACTIVE ALERTS as well as MONITOR SLEEP with SMART SLEEP ALARMS.