The off-road vehicle rescue trailer arm is suitable for a variety of emergency situations. Trailer shackle is usually used with trailer arm, trailer rope, it can be directly connected to the anchor point of the car, but also in the case of trailer rope length is not enough to connect trailer arm and other trailer accessories. There is a small detail that needs to be noted when the shackle is applied to the trailer operation, that is, after connecting the two cars with the shackle, the tightened bolts should be turned half round, so that the shackle can be easily removed after the trailer operation is completed. Because the tension borne by the shackle in the process of the trailer may be too large, it is easy to have a slight deformation at the bolt, resulting in the lock dead, and can not be removed smoothly, and half a circle is to have a margin for the unloading detention, so as to facilitate disassembly.