“Car seals” are single-use security cable seals, so-called due to their alternative use in sealing railway cars, or wagons. Such car seals can also be used in the safe and effective lockout and isolation of industrial valves.

Car seals perform well as single-use lockout devices to seal a valve in the open or closed position, typically for long durations - for example, to permanently secure a sprinkler system valve. To remove the car seal, a cutting tool is required, after which the cable will splay, ensuring that the device cannot be re-used. This effectively prevents unauthorised use of the valves, where this may be dangerous without appropriate safeguards.