Image: Miyota caliber 6S21 quartz chronograph movement

Description: Miyota caliber 6S21 quartz chronograph movement mounted in an Escapement Time Pilot/Flieger Chronograph a Fliegeruhr/Beobachtungsuhr (B-Uhren) style quartz chronograph. The Escapement Time Pilot Quartz Watch is made in China and powered by a Japanese Miyota caliber 6S21 quartz chronograph movement. The 6S21 is part of the 6SXX family of quartz chronograph movements made by Miyota (part of the Citizen group of companies). The 6S21 quartz movement has no jewels and a battery life of about 3 years (assuming 60 minutes of chronograph operations a day). This movement can measure and display time in ¼ second increments up to maximum of 59 minutes 59 seconds. The accuracy rating is ± 20 seconds per month (within a normal temperature range of 5 °C/41 °F to 35 °C/95 °F). The movement in the pictured watch is much more accurate than its accuracy rating. It is powered by a SR927W (399) silver oxide mercury free battery. The diameter of this battery type is 9.5 mm, its height is 2.7 mm and its nominal capacity is 55 mAh. The 'W' at the end of the battery designation means this is a high drain battery version. The battery version suitable for regular and low drain applications SR927SW (395), designation ends with 'SW'. Because both versions have the same nominal 1.55 V voltage and same physical dimensions, it is perfectly safe to use the high drain version instead of the regular version in a watch. High drain batteries are used in watches with features like backlights and audio alarms that require temporary extra power to work correctly.
Title: Miyota caliber 6S21 quartz chronograph movement
Credit: Own work
Author: Francis Flinch
Usage Terms: Creative Commons Zero, Public Domain Dedication
License: CC0
License Link: http://creativecommons.org/publicdomain/zero/1.0/deed.en
Attribution Required?: No