A tourniquet is one of the most important items to have in any IFAK(individual first aid kit) or on a Kit(tactical loadout). For that matter inclusion in a vehicle is a great idea as you never know when an auto accident may occur and someone needs help.
This video shows how to use a CAT Tourniquet (Combat Application Tourniquet).
Please Note: If you are under fire, use the “high and tight” method (over clothes and very high on the extremity). When safe, apply TQ above and closer to the wound (usually 2-3″). Apply a back-up tourniquet above the first one if rebleeding is noted or retighten 1st TQ if no backup available.
Need a tourniquet? Check out this link.