This is a high-quality copper coupling for connecting wheels and motors to facilitate the user to build a robot or small mobile platform motion system. The coupling is fully CNC machined with solid workmanship and high precision. The inner bore is 4 mm in diameter and is suitable for DFRobot's rubber wheels as well as a variety of DC gearmotors. The copper material also makes it extremely durable and reliable.

Specifications:

• Material: Brass
• Motor Shaft Diameter: 4 mm
• Dimension: φ11 x mm/φ0.43 x 0.71 inches
• Weight: 14g ± 0.2g

Warranty: 90 days

• Warranty will not apply if Product fails or is damaged after delivery to you due to accident, abuse or misuse.

Package Includes:

• 2 x Copper coupling (4mm) 
• 2 x M3 screws 
• 2 x M4 Screws