COMPRESSIONZWomen's Compression Trousers - Best Full Leggings Tights for Running, Yoga, Fitness

Could someone please look at the inside tag from these pants and tell me what the percentage of each material they are made from?

Very confused by the sizing. i wear l in all clothes, but waist measurement here would suggest none! across belly button is sadly 39in. suggestions??

Do these pants give good support in the knee area?

I weigh 165 and have terribly swollen legs. I usually wear size 12 what size should I order. I need them for compression.