To activate your Huge Snowflakes Color Changing Necklace, press the button on the battery house for 3 light functions: Flash, blinky & steady light. LED Colors: Blue, Green, Pink One size fits all. Large Snowflake Pendant Dimensions (W x H): 4″ x 3.25″ Small Snowflakes Diameter: 1.75″ Necklaces come ready to use with 3 replaceable AG13 Batteries.