4mm to 5mm Coupling Hub Hello Customers, we would like to inform everyone that we will not be accepting orders until we fix the issue of disappearing shipping cost from your orders. We are still investigating and fixing the settings so that the correct shipping cost will be displayed in every order. Thank you very much for understanding » All Products » 4mm to 5mm Coupling Hub This copper coupler can be used for connection of 4mm to 5mm shafts of RC toys, boats and helicopters. SKU: OTH27407972788 Price: 0.99 $ Product in stock SSL Certificate Quantity Updating cart... This copper coupler can be used for connection of 4mm to 5mm shafts of RC toys, boats and helicopters. Specifications Length: 20 mm Material: Brass Related Products Slide Potentiometer Module Adjustable DC-DC Step Down Converter Module 5pcs TTP223 Capacitive Touch Sensor Remote E3D v6 3D Printer Head (0.5 mm nozzle, 1.75 mm filament) JGA25-370 DC Gearmotor (77 RPM at 6 V)