The word poi means "ball on a string"… and in this case, one that has evolved into a beautiful, imaginative, light-based performance art. Each of our two 4" LED poi balls has a control handle kids can use to alternate three different programmed lighting effects. Aside from being challenging, energizing, and generally tons of fun, mastering poi moves can help kids improve coordination, creativity, and self-esteem. Includes replaceable button-cell battery (and up to 150,000 flashes).