There is a difference between these two products. DM is polymerized from M, and D is actually a double, which is polymerized from two M molecules. When used as accelerator, DM takes less time and the vulcanization speed is slower. Processing becomes relatively easy to control. From the application point of view, DM can be used for relatively complex processing, and M can be directly used for very simple processing. Of course, this is not very absolute, mainly depending on each factory's own formula and technology. It can be used interchangeably to some extent, but it is difficult to be universal when other conditions remain unchanged.