To activate your LED Halloween Necklaces, press the button behind the pendant & watch the spooky shapes flash the night away. Comes on a breakaway string lanyard for safety. Note: Quantity is per necklace. If you order 1 then you will receive 1 of the 4 possible necklace designs. Customers may request a particular design but no guarantees. Dimensions: Eye: Height: 1.78 in. - Width: 1.50 in. Skull: Height: 2.0 in. - Width: 1.25 in. Pumpkin: Height: 2.0 in. - Width: 1.37 in. Mummy: Height: 2.0 in.- Width: 1.25 in. Batteries: Includes 3 replaceable AG13 batteries. - Weight: 0.05 LB