A personal fan! saved my LIFE at float fest, and i bought them specifically because roo was so hot last year. and you can bring several replacement batteries (18650 li-ion if you look that up youll find em) and never run out of power. the batteries cost about 8-10 each but provide about 4 hours of very good fan usage, itll be a life saver and you easily make a lot of friends in crowds by pointing them at other people, anyone will enjoy it! https://smile.amazon.com/dp/B01HRREATA/ref=cm_sw_r_cp_apa_i_jxLkCbS4Q291F

and heres what i bought for spare batteries: https://smile.amazon.com/dp/B074GPX6QP/ref=cm_sw_r_cp_apa_i_1ALkCb1Z78F6E