SockwellWomen's Graduated Compression Stocking | 15-20 mmHg Class 1 Compression Sock

what does synthetic mean? What is the fiber? I see another sockwell that is listed as wool, nylon, bamboo, and spandex.http://www.amazon.com/Sockwel

Are the socks knee high? Or just calf high?

Could you please include New Zealand as shipping destination?

I'm unable to find the size correlations - how do I know whether medium or large would apply - & is it based on foot size or measurements?