Water Estimator For Light Entr, Complies with BS 756 Manufactured from 3.3 expansion borosilicate glass complying with ISO 3585 (ASTM E-438 Type 1 Class A) For use with solvent entrainers that are lighter than water With graduated tube Receivers WE6/23/10T and WE6/33/10T are fitted with a General Purpose ROTAFLO� PTFE stopcock for easy drainage