The Cat-O-Copter rig allows you to fish a bait at any depth by adjusting the sliding stop knot.
Check out the easy to follow step-by-step knot illustrations in the publications:
Fishing Knots – From the reel to the hook:
Fishing Knots & Rigs:
The Fishing Knots Posters:
https://fish-and-bits.myspreadshop.co.uk/all
or
https://fineartamerica.com/featured/1-fishing-knots-andy-steer.html
Disclaimer:
No responsibility in any way is accepted for incidents arising from the use of this material.