Jean_LAMESCH_Sliderules_Collection_BOX_JL10

1769_CONCISE_300_circular

1769_CONCISE_300_circular

CONCISE 300 circular Japanese duplex slide rule, still sold by Concise Co. Ltd. today (2025). Plastic corpus of 111mm diameter., 15 scales. Miniature manual of 36 pages here. Plastic pouch with original manual.