In the 1970s, mood rings that used liquid crystals similar to LCDs became popular. They changed color based on temperature, correlating with our body's surface temperature. Today, we are introducing the Mood Card, which functions similarly to the mood ring. The Mood Card is a fun and creative item suitable for events, festivals, and self-promotion. The pricing includes stock 4-color process front and 1-color back, up to custom 4-color process front and back, with stock round crystal.