Film "F" is a special X-ray film used for mass lung disease diagnose and it is the first time such film is made available in 135. It is a truly a unique film that offer, being coated without anti-halation layer, a high diffusion effect and beautiful grain.
Film is in ISO 100, with 24 exposures.
The datasheet is available here : http://filmwashi.com/datasheet/F100_en.pdf