This distributor, 021.159.007 is in the 1969 to 1971 911S Porsche. It is a clockwise rotation distributor with an aluminum body.
Like the other early small case distributors, this 0231.159.007 uses a clamp. On the 27mm shaft, the clamp is there to hold and adjust the timing. This distributor has a metal spring adjusting window on the side. In 1968, the laws in America were such, that you were not allowed to import a 911S. So in the states, we got the 911L for that year. The 1968 911S in Europe used the cast iron yellow tag distributor, 0231.159.002. In 1969 the 911S used this distributor and ran with a mechanical fuel injection system, or MFI, and a three-pin CDI ignition.
The advance is 15-17° distributor advance, which is 30-34° engine advance. The porsche number is 901.602.031.X.