I bought it as a fishing store.  I use it as a practice plug for casting.  
 

it has a fishing use.  But not sure for what.  A rubber sinker?

Halibut bouncing sinker!

Tom

I’ve seen smaller versions used for walleye fishing.

I think that it's a bait ball for a carp rig. They float. Never used one though. 

 

Oh!    It casts a mile!  

What’s it weigh??

It's weight called a bouncing Betty made by Luhr Jensen.  It was made for steel head and salmon drift fishing.  The idea was instead of using pencil weight or other lead sinkers, an angler could use this heavy rubber ball and hang up less.  It never caught on because it didn't slow the bait down enough, and eliminated the feel most drift anglers were used to feeling.  I think they may still make them.  

9 hours ago, king fisher said:

It's weight called a bouncing Betty made by Luhr Jensen.  It was made for steel head and salmon drift fishing.  The idea was instead of using pencil weight or other lead sinkers, an angler could use this heavy rubber ball and hang up less.  It never caught on because it didn't slow the bait down enough, and eliminated the feel most drift anglers were used to feeling.  I think they may still make them.  

Nailed it.

An American company that named it Bouncing Betty?

 

Somethings I’ll never understand.

 

SMH