Daido D.I.D. Number 40 Roller Chain Connecting Link 4 Pack CL40 4PK | Rural King
Amazon.com: 415 Chain Master Link : Automotive
40/41 Standard Chain Masterlink for Go Kart or Mini Bike
Amazon.com : ORT Bicycle Chain Master Link Single Speed Connector, Metal Bike Master Link Single Speed Chain Connectors, Reusable Chain Connecting Link for Quick Joint Coupling, 2X Black Single Chain Master Links :