Service mark symbol. The service mark symbol (â ), the letters SM in superscript style) is a symbol used in the United States to provide notice that the preceding mark is a service mark.
Size matters: The micro and mini USB connectors are of similar width. But the micro connector is much thinner (smaller vertical dimension). Some product designs were not able to accommodate the height of the mini receptacle and the new thinner receptacle will encourage and allow thinner products.
Figure 2: USB mini and micro A and B. Mini versions of the USB specification that preceded the micro versions have since been phased out. The micro A connector was also phased out in favor of the thinner, sturdier B connector. Micro USB 3 ports can also accept standard B cables.