The Schneider 6 elements enlarging lenses are Componon and Componon-S series. Componar are 4 elements lenses, and they also made a triplet I forgot the name. The difference between Componon and Componon-S is that the first (which is also an older model) has a lower contrast and is suited for enlargements over 5(or 6)x. The S model is high in contrast and suited for enlargements up to 5(or 6)x.

Componons are made as f/2.8 lenses, artificially stopped down at f/4 (just look inside with the aperture large open and will see something like a metal ring sized at f/4, not allowing a larger aperture). I suppose they did this compromise just to keep the lens’ body as small as possible (why, I don’t know). But the lens is genuine a f/2.8.

As for the 40mm focal size, it was made for use with 126 size negatives. I think you can try it with 35mm too, one additional stop closed than normal (I mean f/11 instead of f/8).