I couldn't find the ArcKit Link Component 8.01 in the files published officially at Sketchup Warehouse (almost everything is there except this piece). So I endeavored to reverse engineer it and publish it. This link component is available in all physical kits ; it is also available for sale separately at : https://www.arckit.com/products/8-01-link-x48 You can use 3D modeling and 3D printing to create custom components to integrate with the stock ArcKit ones. ArcKit makes wonderful architecture model building kits for education , hobbyists and professionals: https://www.arckit.com/