Lowy 17 Jewels Hand Wind A. Schild Caliber AS 1187

It's only a metal spacer with four prongs...
That holds the movement in place, but once the case back is firmly closed, the movement and dial do not move around in the case. An inexpensive solution, the watch was probably aimed for "poor men" that needed a reliable and simple watch to tell the time.
When I got the watch, it ran 2 minutes a day fast, but I got pretty lucky pretty easily. I adjusted it once one tick towards slow (the regulator pointed at exactly the neutral position, so I believe no one had ever touched that movement before, the virgin screw slots confirm that too) and it is now running at plus 20 seconds a day and I will leave it at that for the moment.
The watch was lucky to survive my daughter's kicking in the sleep. One night there was an almost full glass of water on the nigh table in the hotel and I was shocked to find the watch laying face down (that was lucky I guess because the stem hole is higher above the surface this way) in a puddle of water. That was a water resistance test of a kind I do not normally recommend.
The next water resistance test came when we met during the PMWFerence 2006 and walked many blocks in pouring rain in Manhattan. The watch is still water resistance with its original square cross section grey O-ring.