This is a 20mm slider. The Antique Silver is made of Zinc plated with 99.9% Sterling Silver. The Antique Brass is made with Zinc plated with brass and the Antique Copper is made of zinc plated with copper.
It is free of nickel, lead, cadmium. Hypoallergenic.
It measures: L-28mm W-23mm H-5mm Hole size: 20.5 X 2.5mm.