Uncommon Finnish Bomb Fuze

[Dreamk]

Finnish Bombs from the 30s and 40s were generally armed with Bofors/Tolfvan nose bomb fuzes designed by Ernst Otto Utter, a Finnish officer who became Bofors representative in Finland before becoming Tolfvan's main technical adviser.
My understanding is that the SKis fuze corresponds to the 1928 Utter's patent while the SKisj fuze corresponds to the 1938 Utter's patent.
1928 patent:


1938 patent:


SKisj:


These fuzes correspond also to the Swesdish Bofors Spetsrör m/1932-39 and Spetsrör m/41
(BTW What SKis and SKisj stand for - S is probably sytytyskytkin = ignition fuze, but what are the other letters for?)

However I found photographs of a Tolfvan bomb with quite different, vanes activated, fuzes (front and rear) :


Can someone identify these fuzes and furnish some data about them?

 

[Tmine35]

SKisj used for 12,5 kg. Skis used for 25 kg - 250 kg.

I have original folder, but in Finnish.

 

[Dreamk]

Could you check in the Finnish leaflets what were the delays associated with both these fuzes? I understand they offered the possibilities of instant impact, and so called "short" delay and "long" delay - but what was exactly "short" and what was "long"?.
Thanks

BTW this is the span of the Tolfvan bomb production in 1938:


and a focus on the small bombs on the left side of the above display, that are in fact part of the earlier Tolfvan / Bofors series from 1930/2


details on these bombs can be seen in the Tolfvan catalog of 1938:
https://digi.kansalliskirjasto.fi/pienpainate/binding/347159?page=1 (up to page 19)
or here (may be easier as teh Finnish archive site is rather slow at some times)
https://sassik.livejournal.com/529855.html

 

[Tmine35]

Short is 15 sec, long is 9 min.

 

[Dreamk]

Thanks TMine!
Can you identify the rear fuze shown here (a very bad photo - difficult to say how this fuze really looks):

I suppose that it is the rear fuze patented by Utter and Tolfvan in 1938 as shown in this drawing