Serial# 2250000- 2810000 from 1960-69. 75mm Xenotar 3.5 or Planar 75/3.5 lens. Heidosmat 75mm F2.8 viewing lens. Synchro-Compur shutter MXV 1/500 to 1,B. Optional coupled meter, Has detachable hood, improved focus screen, eye level viewing. Provision for 220 Film. BayII. Distance scale in meter or feet after Serial# 2298816. Accept plate glass back. After serial# 2299547 accept both 120 and 220 Film and the Xenotar lens had 6 elements. After Lens Serial# 2753002 the Planar lens had 6 elements, self timer.