This space era pocket slide rule come in it’s original box and manual. Made in Hong Kong, marked No 57 and meant for all types of calculations and conversions. The front it for calculation (division, cube root, square root, C.I.F., circumference, etc) using the slider and 2 discs as stated in the instruction paper. The back reads No 57 Hong Kong and is printed with all type of conversions like miles, gallons, speed, square foot, etc . The slide rule is in great condition and made of plastic, it is complete and fully functional. The box is made of perspex, is complete and functioning (small crack in the transparent top). The paper instructions are one side and printed in Hong Kong. The slide rule itself measures ca. 8 cm or 3 1/4 inches in diameter. Check the attached video on how to work your vintage man tool : slide rule operation instructions!