Seven hole plum tube is a kind of plum shaped communication tube, which is made of PVC particles as the main material and other formulations through a unique mold. It is also called plum tube and honeycomb tube or colorful tube. The inner wall of this tube is smooth, and it can directly wear optical cables, which can save working hours. Its structure is reasonable, its use value is high, and its service life is long.

For pipe connection, place the tubular positioning bar upward, clean the outer wall of the end pipe, insert the socket of the direct end, pad a thick board on the end face, and hit the plate with a hammer to make the pipe socket in place. At the socket interface at the other end of the pipe, insert another pipe directly and socket in place, and then extend to the next manhole. In the actual construction, the length of each pipe is not necessarily the same as the length between manholes. In this case, the length of the pipe should be measured according to the actual length and distance of the manholes, and it should be cut with a hacksaw, which must be leveled and neat. After the butt joint is completed, the end extending into the manhole shall be plugged with a pipe plug to prevent foreign matter intrusion.