duplex fitting

例句：

1. 1. The engineer designed a duplex fitting to connect two pipes together.
   工程师设计了一个双联式装配，将两根管道连接在一起。
2. 2. The new car has a unique duplex fitting that makes it easy to switch between front and rear seats.
   这款新车有一个独特的双联式装配，使得前后座椅可以轻松切换。
3. 3.The construction company used a duplex fitting to connect the steel beams in the bridge.
   建筑公司使用了双联式装配来连接桥梁中的钢梁。