It's H5180. Don't you get it?
http://www.promochoice.co.uk/acatalog/RW_H5180_Printed_T-Shirt_215_gsm.html
That Hanes shirt is typically labeled as H5180 in the UK. In the mirror it is backwards, or opposite. She has no shirt on, opposite of what is intended with that shirt. She is not a man, which the shirt is intended for, opposite. She is not beefy, which that shirt was intended for, opposite. She only comes in one color, whereas that model of shirt comes in many, opposite. That shirt is a thing, and she is portraying herself as a human being with emotions, which the raw feel of the picture is indicative of. This picture is beautifully orchestrated to symbolize opposites. Like yin/yang. She is an invariably talented artist who is very cryptic