Stainless steel - keep the look consistent. Curved covers fit over your crimps after you have secured them. Squeeze the covers gently shut with the outer curved notch in your crimp pliers, taking care to align the ends. Could also be used to take up the slack in a necklace with a big gap. Size is the closed or finished size.
P.S. Also great for covering knots in stretchy bracelets!
4mm By the pack of 25.