To start off, sizing wise, I am currently 38" waist and 42" chest so I ordered based off the sizing chart provided the XL and it fits snug but comfortable. But its supposed to be snug right? :)So I just got done using this Ningmi mens sauna sweat jacket for the first time and it works just as others have described.I hit the heavy bag/punching bag for exercise usually for 45-75 minutes a day, 3-4 times a week. I usually sweat fairly good anyways but now that its colder (My heavy bag is in my unheated garage), I still sweat but not like I usually do when the temp is over 55 degrees or so unless I put extra layers on which I don't like doing because I feel it restricts my workout somewhat.Today I put this sauna jacket on to work out, it was about 40 degrees at most outside and no other layers over the sauna jacket. After about 12-15 minutes of working out, I was definitely sweating like I usually do when it is hotter out and continued to sweat as such throughout the entire workout.In between rounds during my 1 minute 20 second rest period, I walk outside my garage and even though it was cold out, I did not feel cold at all so as long as you are moving, the jacket seems to hold your body heat in very well keeping you warm. I did notice after I was done working out during my cool down period outside after about 15 minutes I started to feel a tad cold but as long as your moving pretty good, the jacket kept me warm and sweating.The material is very form fitting and somewhat tight and its supposed to be like that but I also felt like it supported my back and arms very well during my workout due to its compression type feel. Going into my workout today, my back has been sore and tight the past couple days but after my workout, my back felt great. Could have been just from me working out but I feel the compression from the jacket seemed to help at least a little.So based on my first time use, I'm very happy with my purchase.Now with all that being said, I know we live in a world where everyone complains about pretty much anything anymore so I will try and list a couple things that people will probably complain about (not me, I could care less but those of you know who you are ;) )1.) It does have a strong smell to it. So far, I have washed it in the washing machine on a cold gentle cycle and have used its once so far (as of this review) and it still has a strong smell to it. I Imagine over time it will get fainter and disappear at some point but just know before you purchase it, it does have a strong smell to it.2.) It fits snug. But its supposed to be snug. lol I know, I know, its obvious but you know how some people can be. LOLI currently have a 38" waist and 42" chest and based on that, I ordered the XL since according to the provided sizing chart that is what I should order and it fits snug but comfortable on me because it is "stretchy". Its also very soft and not restricting at all.As for me washing it in the washing machine on a cold gentle cycle as I mentioned above, the jacket does say hand wash only but the only reason I put in the washing machine was to try and get rid of the strong smell and I read a few other reviews where others have washed in washing machine with no issues.Washing it in the washing machine did not seem to do anything to the jacket but going forward, I will probably hand wash it as suggested.So like I mentioned above, so far, happy with my purchase and will definitely buy again if and when the time comes I need a new sweat/sauna jacket.I only wish NINGMI sold similar sweat/sauna pants because after using this jacket, I'm curious about trying some sweat/sauna pants now. haha