Keep the trailer in its place, especially while it's being loaded or unloaded. Apply the Glad Hand Trailer Lockout device to lock out access to the trailer's emergency brake connection, preventing it from being moved. To move the trailer, the Glad Hand Trailer Lockout must be taken off the trailer's air line to connect to a truck, which releases the emergency brakes on the trailer. Ideal for use on idle or storage trailers—prevents the trailer and its contents from being moved or stolen. The Glad Hand Trailer Lockout is visible red plastic with built-in key lock (keyed alike).