Disclosed herein are tourniquet devices and systems. A fast-acting tourniquet device may include an inflatable band with a slap band segment having a spring mechanism wherein the slap band is the medium of application of the device to a limb member； an air bladder configured to provide inflation； an air canister chamber configured to inflate the air bladder； a latch configured to secure the air bladder around the limb member； and an optional air valve configured to control release of the device. Also disclosed herein are methods of using the disclosed devices and systems, for example to control local blood flow to a limb or wound.
