Made of high quality plastic PMMA material in clear color, designed with 12 sockets, two layers, each socket is 16mm/0.63" diameter. Ideal for laboratory, can provide clear view of the tube contents and convenient insertion and removal of tubes. For 10ml Test Tube.The hole DIA is 16mm/0.63 inch . Please check befor you but it dear friend ! Test tube set for laboratory and party, holding the tube firmly, avoiding the test tube damage effectively Made of 6mm thick transparent acrylic board, with exquisite and elegant design, strong structure, non-toxic and tasteless. It can be used for scientific experiments, plant propagation and storage of cooking spices. You can also put pens, razors on the acrylic stand