Extensive focus tests were performed to find the most distracting sound to the common security guard.
A Cry Baby is an item which can be thrown and activated to make a noise which distracts guards in a radius of 8 tiles (measured by Euclidean distance). After being thrown, the Cry Baby can be picked up again; it has a cooldown of 1 turn.
Cry Babies are found in the Contingency Plan DLC. They can be bought from some Nanofabricators for 300 credits; additionally, Olivia starts with one.
A Cry Baby is a suspicious item, and will be picked up if a guard investigates the tile it is deployed on. Guards never see a deployed Cry Baby from a distance, and they will not pick it up if it is dropped on the floor without it being deployed.