Muscle t-shirts are usually made from cotton, polyester, or a mix of the two. This is made from 100% polyester. Polyester t-shirts tend to be silkier, stretchier, and more resilient than cotton (and these ones). While cotton is often softer, thicker and less breathable. Cotton also shrinks in the dryer. I personally prefer polyester for muscle shirts. It's not that hot for me. It's also less spongy than cotton, so I don't stay wet for as long when I sweat. Taking it to the window I could see clearly through the fabric of this shirt. But it's still thick enough that my skin doesn't show through when wearing it. I like the big size. Not too wide and not too narrow. I own a lot of Russell Athletic muscle shirts and have worn them with a mixed fit, sometimes too baggy (like Dri-Power Performance ASIN: B07M5HSZ8M) or fitted (like Regular Performance Muscle Shirt ASIN: B00MOV1NKO). According to Goldilocks, "Ahh, this mush is just right." Remember I'm a 6ft tall male with 195lbs so the fit will depend on your girth. The black and gray pattern has an original reptile look. Overall a good seam. The only annoying thing is the 3.5″ long label, but luckily it can be cut off (there are even scissor marks showing where to do it). Besides, it's easy. I weighed the entire shirt (large size) at 2.7 oz (78.5 g). The measurements I took (with the shirt lying on the floor) are waist 21 inches (21 inches), center back collar to bottom of shirt 29 inches (29 inches), and top of shoulders right to left 16 inches. (16 inches). Tag Info: Made in Vietnam. Machine wash warm. Wash with like colors. Only non-chlorine bleach when needed. Tumble dry low. Cold iron. Do not dry clean. Would happily buy more t-shirts from this brand and style.