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Jack Traps made in ME
The egg sinker sits on the bottom of the lake. When the fish grabs the bait and pulls line, the sinker stays in the same spot and the line simply slides through the sinker. That is until you set the hook. I don’t fish this way but lots of others do.
Here is a link to a photo that shows the rig.https://newbayfisher.wordpress.com/2013/05/25/the-slip-sinker-rig-introducing-a-classic/