To activate your Glow Stick, bend it until you hear it crack, then shake it up. This releases the chemical within the stick - immediately it will GLOW & lasts 6 to 8 hours. NOTE: PRICING IS PER PIECE. Dimensions: Height: 6.0 in. , 15.24 cm. Width: 0.75 in. , 1.9 cm. Lanyard Necklace: Approx. 31.0 in. Glow Stick Color: White Batteries Batteries are not required for this product. Packaging: Items in a foil bag - 25 pieces per bag & 500 pieces per carton.