This is an updated illustration based on an early 16th century woodcut allegedly done by the legendary alchemist Paracelsus. It is purportedly a salamander, a rarely depicted fire elemental spirit. This image will confer upon you the higher and more refined aspects of fire, such as passion, intellect, and a tendency to reach upward into the higher spheres. ([READ THIS] a note on sizes: I used to advise on sizes but there is just too much variation between people. I'm about 6'2, and skinny, and I wear a medium. The medium is pretty large, but for some guys it's not big enough. Honestly the only way to make a safe bet is to check out the sizing guide below and measure yourself or one of your shirts that you have that fits you well. I can't do returns because they're all made to order so, it's not like I have a ton of them all here at the studio. If you want to order a bunch I'd probably advise getting one and then seeing how it fits and then going for more.
On my end, the data I can give you is that after advising that if you're torn between the medium and the large to get a medium, it worked out for most people, but some guys have bigger arms or actually needed the large so, like I said, basically gotta measure yourself.)