https://www.sigmaaldrich.com/JP/en/product/aldrich/z153281
Polypropylene NMR tube caps NMR tube size, 5 mm- white cap tubes
NMR tube caps NMR tube size 5 mm; Synonyms: cap tubes,nmr tubes,plastic end cap at Sigma-Aldrich
nmr tubesize 5white cappolypropylenecaps