The Unitas 339 watch movement is an open face calibre that features a stop function with a pillar wheel mechanism. It is often listed in catalogs as the Heuer 340 movement, indicating a likely association with Valjoux. The movement offers various functions including a timer with a 60-second accuracy of 0.2 seconds and a 30-minute range, utilizing the pillar wheel system. Additionally, it provides an alternate option for a timer with a 30-second accuracy of 0.1 seconds and a 15-minute range. The Unitas 339 movement is stem wind and incorporates a sweep second hand. It excels in its Timer Function, which is a significant aspect of this movement.