New without tags is an adult unisex short sleeve t-shirt.  This is from the Nov. 11, 2018 Las Vegas Rock 'n' Roll Marathon.  This was the shirt given to runners, therefore, there is no tag, but it is new.  Label on the inside seam notes it is 100% polyester, and is an adult unisex size XXL.  It is black with a screen print on the front with the marathon logo and date, featuring Las Vegas iconic images, such as the welcome to Las Vegas sign, the Sphinx, Eiffel Tower, Paris ballon, pyramid, ferris wheel and more.  The sleeve has a screen print that reads: Rock 'n' Roll Marathon Series.  The shirt is quite thin - great for summer runs.  I tried to show my fingers showing through it when it is held to the light.  It weighs 6.2 oz on my digital postal scale.  I measure it laying flat as follows:  It measures about 24-1/2" wide from armpit to armpit (or 49" around).  It measures 31" long from mid shoulder to hem.