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I found this on your stock list, please quote: Thanks.

GIA 17398309 0.710 F VVS1 Ex. Ex. Ex. None Y 圓形 Medium - -
GIA 17594879 0.720 D VS1 Ex. Ex. Ex. Strong Y 圓形 Thin - -
GIA 17534153 0.750 D VS1 Ex. Ex. Ex. Medium Y 圓形 Thin - -

What is difference betwwen None, Strong, Medium? what is better?