Up for sale is a classic C-Thru Ruler Company Model PS 69 Proportional Scale. This circular slide rule is a fantastic piece of analog equipment, perfect for graphic designers, photographers, illustrators, and printing professionals who appreciate vintage drafting and calculation tools.

This tool allows you to quickly and accurately calculate the percentage of enlargement or reduction needed for photos, artwork, and layouts.

Key Features:

• Dual-Scale Calculation: Features inner and outer scales to line up original and desired reproduction dimensions.

• Automatic Results: Once you align your dimensions, the new size and the percentage of reduction/enlargement appear in the window automatically.

• Collectible & Functional: A perfect addition to a design studio, workspace, or a collection of vintage office and drafting supplies.

• Brand: Made by the C-Thru Ruler Company (Bloomfield, CT), a trusted name in high-quality professional drafting equipment.

Specifications:

• Model: PS 69

• Type: Circular Proportional Scale

• Dimensions: Approximately [Insert Diameter in Inches]

This is a great, functional piece of design history. Whether you are looking to use it for analog projects or simply want a cool retro desk accessory, this proportional scale is ready for use.