Distagon 1.2/25mm

It seems to be a lens for 16mm film, but my reference book states that it is for 35mm film.

Specification of DISTAGON 1.2/25MM  

Manufacturer "OPTON" (Germany)
Lens system -
Focal lengthf'25.9 mm
Angle of view2ω'57°06'
Effective relative aperturef:nэ1:1.4
Lens lengthΣd78 mm
Front focal lengthS-
Back focal lengthS'27.2 mm
Flange focal distanceZ-
Block lengthB88 mm
Block max. diameterD76 mm
Rear diameterD'41 mm
Front element diameterd147.5 mm
Rear element diameterd227.0 mm
Mount thread -
Distance from rear end of the housing
to the focal plane
l26.2 mm
Aperture blades quantity ?
Frame size 16x22 mm
Weight 550 g