3mm to 4mm Coupling Hub Happy Chinese New Year!! WIDER WIRE & CABLE CO,.LIMITED will be temporarily suspend processing orders starting January 13 due to the holidays. We will resume our operations and process your orders placed on February. Thank you! » Other » 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 5pcs 3D Printer Nozzle 0.4/1.75 mm PCA9685 PWM Servo Motor Driver compatible with Raspberry Pi(Arduino-Compatible) JGA25-310 DC Gearmotor (44 RPM at 6 V) JGB37-520 DC Gearmotor (319 RPM at 12 V) JA12-N20 DC Gearmotor (250 RPM at 3 V)