1:PTFE stopcock, 2:straight shape material:heat resistant 3.3 borosilicate glass 1,PTFE stopcock for burettes,2,Separatory funnel etc,3,straight shape4, Material:heat resistant 3.3 borosilicate glass, heavy wall5,Joint 12.5# 14.5# 18.8#6, Scope of application:for scientific research, teaching, medicine, and chemical industries made of PTFE and glass PTFE Stopcock straight shape