Sizes : big-size, middle-size, small-size. Product structure : up wing, down wing Product instruction : The products are made by medical polymer materials. Sterilized by EO gas; sterile, non-toxic, pyrogen free. The two wings are in highly smooth rim, and distance between the two wings can be adjusted. Technical indication: in accordance with YY 0036 Scope for use : The products are used for vagina examination in clinic