Sellita SW 221-1

The SW 221-1 is an automatic movement manufactured by Sellita and modified by Mühle Glashütte with their patented Woodpecker neck regulator. It provides a 41-hour power reserve. The movement powers watches in Mühle's 29er collection and remains in production. This is not an in-house caliber; Mühle modifies standard Sellita bases for use in its tool watches.