My doctor prescribed compression socks with a rating of 20 to 30 mmhg so I just order ones with that rating. If you know what compression rating you previously used I would stick with those and discuss it with your current doctor. You can order them online. I buy ones that I found online that have side zippers that make them easy to put on and take off. Most of them have size charts where you measure your foot, ankle and calf and the chart will tell you the size you need for their brand.