After reading a couple articles , I decided to make one myself.
This tool is made from 3/8" steel tubing for automotive repairs.
Copper would work fine also.
I started with an 8" piece and turned the end 90 degrees with a tubing bender.
On the straight end , I crushed it with a vice and tapped it a bit with a hammer.
The flattened portion is about 2 1/2" long as shown.
The crushed width is about perfect and the tool works well , it's a bit long , but I can't remember how much too long it was.
The photos should explain what I can't.
Total cost was around $0 because it was scrap at my shop.
I keep it in my tool pouch always .....