Iron plating universal joints, can be rotated to change the transmission direction. Suitable for use on car and boat models, small and delicate, durable. 
 
Product Name:Universal Joint Coupling
 
Material:Iron plating(45 steel)
 
Delivery list:Universal joint, send screw spanner (each customer send a spanner)
  
Product Description:For example, 4*5mm, i.e. 4mm and 5mm holes on both sides respectively, can be inserted and fixed into the
corresponding size and diameter of the shaft or motor.
 
Scope of use: motor, straight shaft use, suitable for model cars, model boats, robots and other types of metal adapter use!
 
Size introduction: (each weight varies, for reference only): 

2.3*2.3, 2*2.3, 2*2 OD 8mm, length 18mm, weighs about 8g, side M3 fixed.
 
2.3*3, 3*3, 3*3.17, 3.17*3.17 OD 9mm, length 23mm, weighing about 8 grams, side M3 fixed. 
 
3.17*4, 3*4, 4*4 , 2.3*4 outer diameter 9mm, length 23mm, weighing about 7.5 grams, side M3 fixed. 3*5, 
 
3.17*5, 4*5, 5*5, 4*6, 5*6, 6*6 OD 11mm, length 23mm, weighs about 10g, side M4 fixed.
 
5*8, 6*8, 6.35*8, 8*8 OD 14mm, length 35mm, weight about 20g, side M4 fixed. (The model has a card spring design fixed, so there is a little tightness, is normal!)
 
8*10, 10*10 OD 16mm, length 35mm, weight about 28g, side M4 fixed.