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. » Connectors » 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 JA12-N30 DC Micro Gearmotor (280 RPM at 12 V) Antenna (433 MHz, 4 dBi) Digital Watt Meter max DC 60V 100A JGA25-310 DC Gearmotor (7 RPM at 6 V) SG3525 PWM Controller Module