He pointed at me with the stem of his pipe.

他用他的烟斗柄指着我。

《柯林斯英汉双解大词典》

Valves should be installed in the (stem) vertical position with the pipe flow horizontal only. For installations other than this, please consult factory when ordering.

阀门应该只能安装在水平流向的管线上，其阀杆应该垂直向上。如果需要其它方式的安装，请在订购阀门时咨询工厂。

youdao

Globe pattern check valves should be used in horizontal pipe runs with the stem straight up.

截止阀结构的止回阀应该用于水平管道，阀杆垂直朝上。

youdao

The mermaid's intricate tresses, crowned with a garland of flowers, flow back to meet up with her finely wrought fish tail and the pipe's amber stem.

FORBES: Where There's Smoke, There Are Buyers