We just got off a cruise and had no issues with bringing this onboard. I was with a group and we all had one in our rooms. In fact, this particular one was on many lists that I read about ‘must haves’ for cruises so I had no idea they were prohibited?

Power Strip with USB - 2 Outlets... https://www.amazon.com/dp/B081ZQKXN4?ref=ppx_pop_mob_ap_share

It was super helpful because there were only 2 outlets in the room by the vanity and we had at least 4 things to charge at a time (our phones/iPad/watches/AirPods).