i have five size 16 17 18 19 20 2 Please tell me need siz read my all message and see phot Don't just look at half ,check yourself . use my photo way , you will have best fit siz usually size17 for women. size 20 for me if you not tell me need size when you make order i will send size 17 for women size 20 for ma 1 inch = 2.54 c if your arm about 15.8cm size 16 will fi if your arm about 16.3cm size 17 will fi if your arm about 16.7cm size 18 will fi if your arm about 17.9cm size 19 will fi if your arm about 18.4cm size 20 will fi if your arm about 19cm size 21 will fit