A.W. Faber (Castell) - System Rietz No. 51/94 - Vintage Slide Rule with Original Box - c. Mid-20th Century Up for auction is a magnificent vintage slide rule by the renowned manufacturer A.W. Faber (later Faber-Castell), model System Rietz 51/94. This classic analog calculating instrument was an indispensable tool for engineers, architects, scientists, and students throughout the mid-20th century before the advent of electronic calculators. The "System Rietz" layout features standard scales (such as A, B, C, D, K) alongside trigonometric scales, making it a quintessential piece of scientific history. The slide rule comes complete with its original matching cardboard storage box, featuring the manufacturer's embossed gold branding. A wonderful collectible for enthusiasts of vintage technology, scientific instruments, and mid-century industrial design. Specifications & Condition: Maker: A.W. Faber (Castell)  Model: System Rietz 51/94  Type: Analog Slide Rule (Calculateur / Rechenschieber) Included: Slide rule with clear glass/plastic cursor and original branded box  Condition: Good vintage condition. The instrument shows minor signs of age and handling consistent with use, but the scales are crisp, legible, and the cursor moves smoothly. The original box is intact with minor shelf wear. (Please examine the detailed photographs for the exact cosmetic condition). Shipping & Packaging: Will be shipped securely packaged with tracking and insurance.