With Vigreux indentations.Used with P3770 25mm immersion thermometer and D3707 distillation receiver. ● Material:Borosilicate glass ● Color:Clear ● High temperature resistance,corrosion resistance,chemical resistance ● Used in small doses of distillation of matter ● Low vacuum interlayer trace distiller ● Under the condition of low make fractions don't touch the wall directly drip into the bottle ● Joint size 10/18:10 refers to joint diameter,18 refers to joint height,other specifications and so forth