Abstract: Flexible graphite granules prepared by a process comprising agitating vermiform expanded graphite masses having a bulk density of not more than 0.01 g/cc in a liquid have been found to be extremely suitable for producing a flexible graphite product, even with a low density, having an excellent shape-retaining property as well as a shapeability and exhibiting strong mechanical strengths.

Abstract: A drain trough having longitudinally lined plastic round pipes and plastic connectors for connecting the pipes to each other in order to form a long drain trough. The plastic pipes each has slits longitudinally and intermittently extending and formed in the peripheral wall of the pipe. The inner space of the pipe has a partition wall of various shapes, which wall extending along the length of the pipe so as to divide the space into two, three or four compartments, through which drain water flows. The drain trough is slantly buried in the ground or track and field.