outside diameter of bubble cap

例句：

1. 1.The new car has a larger outside diameter than the old one.
   这款新车的外径比旧款大。
2. 2.The pipe's inside diameter is 30mm, and its outside diameter is 40mm.
   这个管子的内部直径是30毫米，外部直径是40毫米。
3. 3.The engineer calculated the outside diameter of the pipe to ensure it would fit through the opening.
   工程师计算了管道的外径，以确保它能够穿过开口。