This camping trip can be installed in campgrounds, farms, entrance areas, gates, restricted areas etc, and setting it with blanks to alert them when someone, or something, breaches their area. The alarm signaling device uses a low-placed and concealed trip wire, tethered to the device itself which creates a loud audible alert when the activator pin is pulled easily attached to trees, posts, or frames via the screw holes or zip tie notches. Every camping trip enthusiast or anyone who needs to effectively protect their property should not miss this perimeter tripwire alarm device. Perimeter trip alarm system is for outdoor use only. Please keep away from flammable materials and use with caution. Our devices don't hurt anything, just make a loud noise to alert you when you need it. Color: As Shown Material: Metal Package Contents: 3 * trip wire Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.