The Kasper 900 is rather rare pallet lever movement of the late 1950ies. Its construction was contemporarily modern with a directly driven center second and a Monorex shock protection. It was available with 17 and 21 jewels.
Since it was equipped with a screw balance and a long regulator arm it could achieve good precision results, although it was beating with the still modern slow beating frequency of 18000 A/h.
The clearly arranged construction with its slanted hat-shapred gear bridge is nice to see.
The gears work as following:
Mainspring barrel - center minute wheel - third wheel, center second wheel - escapement wheel.
In the side view, you can see the stacked construction, where the center minute wheel is beared under an own bridge with two jewel bearings. Above that, there's the center second wheel.
The toothing of the escapement wheel is interesting, since it has got two toothings, of which only the upper one is used for the connection to the center second wheel.
The jewel bearing of the minute wheel is a bit unusual and technically not really neccessiary, but it helps easier achieving the popular number of 17 rubis.
Also on the dial side, the Kasper 900 makes a very clean appealing. The only noteable thing is the odd shape of the setting lever spring of the yoke winding system, which reminds of a bent-to-back arm.
The version with 21 jewels, including the watch with the black dial, is a kind donation of the Ristow family. Thank you very much for the support of the movement archive!