Kimble kimax educational grade burets these economical and versatile burets are ideal for use in educational institutions and for many general laboratory procedures. 17040k supplied with a ptfe stopcock plug easy-to-read durable black enamel scale for 17040k and 17021h-50 17121h supplied with a ptfe threaded stopcock assembly and a precision ground tip 17021h supplied with a ptfe compression fit stopcock assembly and a precision ground tip 17021h, 25 ml buret has a permanent brown stained scale kim-kap dust cap is included funnel fill style buret manufactured from 33 expansion, low extractable borosilicate glass conforming to usp type i and astm e438, type i, class a requirements. Warning: this product can expose you to chemicals including tetrafluoroethylene, which are known to the state of california to cause cancer. Prop 65 warning