This effect was invented by E.J. Moore and marketed by him as Link-King Ropes c. 1951, it was later marketed by U.F. Grant and Tannen’s.
This set was released by Bob King Magic and is easily the best set of Linking Ropes I have seen.
Effect: Ever wish you could do the linking rings at a moment’s notice without having to carry heavy steel rings around with you? Well, your wish has come true. Here is a genuine linking ring routine with ROPES. So compact you can tuck them in your coat pocket and you’ll never know they’re there! Magician shows 3 short 2 ft. pieces of rope and allows the spectators to tie each one in a circle with a genuine knot. Then without switching the ropes or fingering the knots (the knots may be sealed by the way) he proceeds to link and unlink the solid rings of rope in a series of bewildering and confusing designs. At the finish the spectators are allowed to untie all 3 knots and verify that they are genuine and have not been tampered with at all. The effect requires no skill and is mechanical in every respect but impossible to detect. Complete with rope and routine.
(Notice: Includes: Printed Instructions.)( Post Source: martinsmagic.com - click for details )