Amazon.com: Luanxu 4.5 mm Stainless Steel Bead Chain for Blinds & Shades with 5 Connectors, Fix or Replace for Broken Roller Blind Curtain Chain, Great Pulling Force & Rustproof (#10, 3 Meters) :
How To Replace A Roller Blind Chain | Checkatrade
Amazon.com: 150 Yards/Roll Lift Cord 1mm Braided Shade Roller Blinds Cord White Pull String Rope for Aluminum Blind Shade Repair and DIY Crafts Projects(Max Load 66lb)