59 feet 1 1/4 inches in length designed by Ralph J. Snelson and R. Clayton Brough and built by students at Springville Junior High School, Springville, Utah. Guiness Book of World Records, 1978, Sterling Publishing Co, New York, NY USA.

320 feet 11.1 inches in length completed in March, 1979, by students of Alvirne High School, Hudson, New Hampshire. Guiness Book of World Records, 1980, Sterling Publishing Co, New York, NY USA.

323 feet 9.5 inches in length completed on Nov 11, 1979 by Greg Maggs and Robert Kolstad at the University of Illinois College of Law Building in Champaign, Ill. Guiness Book of World Records, 1983, Sterling Publishing Co, New York, NY USA.

Slide rules of record proportions like these are far too large to fit in standard contemporary office furniture , for slide rules like these you must have dedicated storage areas and while they are great for showing and exhibits they are extremely impractical for everyday use.