PMFJI. If you look closely at the shutter's aperture scale, you'll see that it is scaled for a convertible lens. The combined lens' maximum aperture is f/4.8.
Originally Posted by E. von Hoegh
Ilex' Acutar was a tessar type, said to be a clone of the f/6.3 Commercial Ektar.
Tessars aren't convertible, some plasmats are. The likely convertible plasmat was Ilex's own 215/4.8 Acuton, said to be a good lens.
Which were you thinking of? Oh, and by the way, I find Ilex' nomenclature nearly as confusing as Graflex'.