Hello Hobby Open-Ring Metal Snap Fastener Kit, Nickel Plated Brass, 10 Sets and Tool - Walmart.com
Amazon.com: Sturdy Alloy Spring O Ring,Spring Clip Round Carabiner,Metal Circle Trigger Rings Firm Clasp Snap Hook Key Ring Buckle Fastener,Range 3/4 inch to 2 inch Size (Silver, 35mm(1.37"))