These pliers will form synclastic shapes like bracelets, bangles, hoop earrings and any other form that requires a concave surface. They are very easy to use. They come in three sizes 3/8", 1/2" and 3/4".
The 3/8" will form a deep synclastic form with tight radiuses.
The 1/2" and 3/4" will do similar forms but with less curve. Can be used with silver, gold, brass, aluminium, even a thin guage stainless steel. (You might not have to anneal your aluminium.)
Can be used with copper, silver, gold, brass, even stainless is possible. Aluminum works fine as well. Metal can be annealed or not. The gauge is limited by your ability to open and close the pliers (hand strength).