A Balisong is a type of small knife whose handle doubles as a blade cover. The handle is made in two halves that rotate independently to cover the blade. This type of knife originates from the Philippines and is quite popular in the Southeast Asia, both as a handy day-to-day tool and as a weapon, but owing to its compact size, concealable nature and ability to speed-deploy, it is legally restricted in many countries. Blunt versions are often sold for training purposes.
A balisong can be swiftly deployed by flipping out the blade when held by a trained user. This technique is also displayed on-screen by Alicia in "Do Not Disturb".
A balisong originally belonged to Jack Kipling and was first seen when he cut Alicia Clark loose in "Blood in the Streets." She subsequently stole it from his back pocket while he was distracted teaching her the radar in "Captive" and it became her melee weapon of choice for seasons 2 and 3. Alicia first used it to fight off zombies in the Rosarito Beach Hotel in "Do Not Disturb". In "North," Alicia used it to kill a person for the first time when she stabbed Andrés Diaz with it to save Travis Manawa's life.
The status of Alicia's balisong is currently unknown. In season 4, Alicia replaced it with a gun mount she got at Whirlin' Wavez in "Buried" and sharpened under unknown circumstances.