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 JGA20-130 DC Micro Gearmotor (24 RPM at 12 V) 20pcs 2 x 70 mm Shaft 20pcs XH2.54-6P Straight Pin Header and Connector JA12-N20 DC Gearmotor (300 RPM at 6 V) JGB37-545 DC Gearmotor (960 RPM at 24 V)