You need to size up at least a half size. I wear an women's 8.5 and ordered a 9. Still too small. I have a very narrow foot and this felt too tight in the arch.

If you haven't worn the shoes out completely, you should be able to find inside each shoe a tag with a upc barcode as well as a number. That number is the identifying number for the model.

Nike TNs stands for "Tuned Air," like the tn berlin which is a technology that Nike uses in some of its shoes to provide cushioning and stability. The technology consists of air-filled capsules in the sole of the shoe that can adjust to the wearer's weight and movements to provide a customized level of support.