compression shirts?

I've heard mention of compression shirts before.  What are they?  What are they for?  Do you buy them too small in order to "compress"?  Where do you get them? Thanks, guys 7 days post op and doing great!!! Al

Al, Here is a link to an example of a compression shirt.  They were origionally designes for athletes to whick away moisture from the body to keep the athlete cool in the summer or warm in the winter.  They also help people with loose skin to suck it in a little and if I am not mistaken, most people wear them under their clothes for that reason.   I use the compression underware because my thys are like cottege cheese and rub when I run.  Many people refer to this kind of whicking material as under armour because I believe that they were the company that invented it.  Many companies now make the stuff and my favorite for the price/quality has been the adidas underware because I got it on sale and I am to cheep for the "real" under armour. Scott http://search.ebay.com/nike-compression-shirts_W0QQfkrZ1QQfn uZ1

I WARE THEM UNDER MY SHIRTS AND THEY MAKE A BIG DIFFERANCE IN HOW MY SHIRTS FIT. I WARE A 1X SHIRT BUT I WARE A MED UNDERARMOR SHIRT . THEY MAKE YOU LOOK LIKE YOU HAVE  A BODY TONE AND THEY MAKE YOUR SHIRTS FIT LIKE A NORMAL PERSON. THEY KEEP YOU VERY COOL AND THEY ARE WELL WORTH THE 25 BUCKS A POP. THEY HAVE ALL KINDS FROM TAINING TO COMPRESSION. MAKE SURE YOU GET THE COMPRESSIONFOR THE BEST SUPPORT. THE BOXERS ARE GREAT TO. THEY REALLY TIGHTEN THE THIGHS UP

There are several different makers of compression clothing. I wear Under Armour shirts and shorts every day and love it. It's basically like wearing tight/spandex. It keeps everything tight and reduces what I call the "jiggle factor." I started out just wearing it to to the gym but liked them so much that now I wear them under my clothes all the time as underwear.

Russell Athletic also makes stuff like Under Armour does, now.  Except in bigger hard-to-find sizes.  And yes they feel very good.  Too bad I can't find any in white, then I'd wear it everyday.  I have several 5x ones and two 3x ones to "grow" into.