Ok so it's quite a strange name I agree! This tools full name is a 'Zinc Came Bender' and it is a great little piece of engineering which allows crafts people to create perfectly smooth curves in the rigid pieces of zinc which are used when strengthening and edging stained glass panels.
It basically consists of two movable rollers and a handle to turn them.
The original piece of straight zinc is slowly rolled through the machine and each time the rollers are tightened a little.
This means a slight curve is developed on each pass through the machine.
With time, this curve can be made as gentle or as pronounced as you like.
The zinc will still remain rigid and its profile perfect and it will add a lot of stability to your window.
The advantage of using zinc came for edging stained glass work, is that compared to the traditional lead came, zinc is a lot stronger and rigid.
You can make larger and more ambitious works and if you combine this with the use of the came bender tool, the sky is the limit.
Using curves in stained glass are often preferable aesthetically than simple straight lines, so this tool will help you if you want to develop very smooth and organic forms in your piece.
Costing around $100 this specialist tool really is worth the cost.
Very few companies make this tool so it is almost a trade secret amongst stained glass experts, but thanks to the net, the secret is now out!