【求助】帮忙翻译一下这句话

玻璃提取套管,孔隙度1(这里应该是1%吧?),尺寸约30×100mm.
对这个不熟悉,期待更准确的解释

就是1，所以不太明白

孔隙度是孔隙体积与总体积的比值，所以应该用百分数表示，粗糙的玻璃，其孔隙度一定很大，这里的1应该是对玻璃材质的一个要求吧

I have not idea, but does it relate to grading or size of particle retention?
http://www.labfilter.com/article.asp?id=196&title=About_different_glass_filter_grades

“but its impinger has a porous glass filter plate of porosity 1 (ø of pores 100-
160μm) at its end.” At page 112 of
http://e-collection.ethbib.ethz.ch/eserv/eth:24354/eth-24354-02.pdf