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. » Gearmotors » 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 JGA25-370RC DC Gearmotor with Extended Axis (13 RPM at 6 V) Wemos D1 R2 Uno ESP8266 WiFi Development Board JA12-N20 DC Gearmotor (300 RPM at 12 V) 10pcs Oval Plastic Building Block – Orange 10pcs Silver Slotted Aluminum Heat Sink (13x13x11mm)