types of joints :  1, both ends are external joints  WW type   

                 2, both ends are internal joints   NN type

                 3, one end is external joints , the other with bottom   WDtype   

                 4, both ends are side cut from the trough  QdQd type

1. OEM Manufacturing welcome: Product, Package...  
   2. Sample order
   3. We will reply you for your inquiry in 24 hours.
   4.  after sending, we will track the products for you once every two days, until you get the products. When you got the goods, test them, and give me a feedback.If you have any questions about the problem, contact with us, we will offer the solve way for you.