Siji Muge’s vacuum tubes are commonly divided into two types: space tubes and crystal diamond space tubes. There is another type called special effects tube, which is very rare and is often used for large-area installation in residential buildings. The logo of the space tube is that about a quarter of the upper end of the inner layer of the vacuum tube is engraved with the spiral trademark of Siji Muge and the words space tube (I have never seen the special effects tube. Sorry). The logo of the Jingzuan space tube is on the outside of the vacuum tube. There are yellow scales on the layer from zero to twenty-five degrees and from zero to two hundred and fifty degrees respectively. In addition, there is a spiral trademark and the words "Jingzhuan Space Tube" on about a quarter of the upper end of the inner glass tube. What doesn’t exist is fake.