2mm to 4mm Coupling Hub Please allow 4-6 days processing before ship out. For gearmotors or similar motors, we don’t ship using epacket and will use regular shipping if needed. Please note that regular shipping like singapore post might take 45-60 days to deliver, epacket 20 -35 days to deliver Thank you for understanding. » Other » 2mm to 4mm Coupling Hub This copper coupler can be used for connection of 2mm to 4mm 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 2mm to 4mm shafts of RC toys, boats and helicopters. Specifications Length: 20 mm Material: Brass Related Products 20pcs 6mm Pulley Wheel 2pcs Mounting Hub for 3 mm Shafts JGA25-370 DC Gearmotor (58 RPM at 6 V) XS3868 Stereo Bluetooth Audio Module Adapter Board JGA25-310 DC Gearmotor (177 RPM at 12 V)