Synclastic Pliers 3/8" These pliers will form synclastic shapes like bracelets, bangle bracelets, hoop earrings and any other form that requires a concave surface. They are very easy to use. The 3/8 forms deep syclastic forms, 1/2 and 3/4 will do simlar forms but with less curve. Can be used with copper, silver, gold, brass, even stainless is possible. Aluminum works fine as well.