3mm 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. » All Products » 3mm to 4mm Coupling Hub This copper coupler can be used for connection of 3mm 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 3mm to 4mm shafts of RC toys, boats and helicopters. Specifications Length: 20 mm Material: Brass Related Products 500 W Inverter (12 VDC to 18, 220, 360 VAC) Red Push Button Module JA12-N20 DC Gearmotor (1000 RPM at 12 V) 5pcs 3D Printer Nozzle 0.4/3 mm Solid State Relay (250 V, 2 A)