original rigid case: Nikon CL-11
variants and serials
2/1970 F mount serial from 230011
– Filters Built-in: L1A, Y48, Y52, O56, R60
1977 ai mount serial from 240409
– Filters Built–in: L1A, Y48, Y52, O56, R60
1982 ai-s mount serial from 243001
– Filters Built-in: L1BC, Y48, Y52, O56, R60
– rough opaque finish cap