It's definitely a sublimation cuff or a cuff for a standard heat press. The second part that says caution is part of the heat attachment for baseball caps.
Example with attachments: https://www.amazon.com/Mophorn-Multifunction-Sublimation-Baseball-Transfer/dp/B01HPV87O2/ref=sr_1_5?s=arts-crafts&ie=UTF8&qid=1483977288&sr=1-5&keywords=heat+press