Wire protector, Accu-Guard™, gold-plated brass, 4x4mm tube with 0.5mm inside diameter. Accu-Guard™ wire protectors are designed to protect wire against wear from clasps and other sharp-edged components. Similar to bullion or French wire with a rigid, pre-curved horseshoe shape to cradle and protect your bead cord from fraying. Inside hole diameter is 0.5mm. Due to manufacturing process, sizes vary slightly.