Hans Tröger High Precision, Circular Slide Rule. Nice! This is an oversized rule, 11.25 inches (28.5 cm) in overall diameter.  The scales are 9 inches (23 cm) in diameter, or 28 inches (72 cm) in circumference.  The scales afford 3-digit precision over the entire range of values, and 4-digit precision can be estimated over part of the range, roughly between the 1 and the 2.

A knob on the back helps one turn the inner scale. See photos. It helps to gently hold the cursor in place with one's thumb while the scale is being turned.  Any instructions or case have unfortunately been lost over the years.

Satisfaction guaranteed! You may return the slide rule for a full refund for any reason, or no reason at all, within fourteen days. Purchaser pays return shipping.

Shipped within three business days, usually sooner.  

All slide rules we ship are very securely packaged.  Most packaging is recycled.  We have shipped slide rules all over the world.  No purchaser has ever reported damage to a slide rule in transit.

Please ask if there are any questions.

International bidders are welcome!  Any import duties are the purchaser's responsibility.  The description and price will be accurately listed on the customs declaration when the rule is shipped.