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 » Connectors » 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 JGB37-3530 DC Gearmotor (12 RPM at 12 V) 2pcs 1 V 100 mA Solar Panel XL4015 5A Adjustable Step Down DC-DC Module (4 – 38 V input) JA12-N30 DC Micro Gearmotor (70 RPM at 12 V) 50W LED with Color Temperature of 3000-3500 K