Colour-coded cards for conference session chairs to signal remaining time to speakers, ranging from green (10 minutes, 5 minutes) to yellow (2 minutes), orange (1 minute), and red (0 minutes), plus the skull and crossbones card for those rare instances when you need to nudge a long-winded speaker away from the microphone.
I always keep these time cards in my toolkit when I travel to chair a conference session. Happily, today at #ASSA2025 there was no need for me to flash the dreaded skull & crossbones card. Many thanks to the organizers of the long-ago EFA2012 conference in Copenhagen for creating the cards!