The Tissot 17.5-21 watch movement, similar to the ETA 717 movement but with lower specifications, is equipped with an early Incabloc shock device. The differences between the Tissot 17.5-21 and the Zentra 295 movements are unclear. There are various samples of the Tissot 17.5-21 movement that exhibit both bridge layouts shown in the archived records. The Tissot 17.5-21 movement is a manual wind movement with sub-second functionality, and it was primarily used around the year 1935.