基本释义:

有孔封头

网络释义

1)perforated head,有孔封头

2)improved header with punched baffle,孔板封头

3)spherical-zone shell,开孔封头

4)blank head,无孔封头

5)opening in head,封头开孔

6)Pore stuffed with organic coating,有机封孔