Teeth, spring, lap joint.Recommended for small hands.Excellent for tougher rings in tighter spaces. Max Recommended Wire Thickness (*See Notes Above): Stainless and Titanium (SS/TI): 14gCopper (CU): 12gBronze and Brass (BZ/BJR): 14gAluminum (anodized AA and bright AB): 12g Minimum Recommended Size (*See Notes Above): 19g