The Overhead Door Warning Barriers protect the overhead doors from fork trucks, pallet trucks, and other traffic. Barriers are constructed of heavy-duty, rust-proof PVC. Featuring highly visible, black and yellow safety tape and 2 American flags. Kit includes 2 15’L chains with quick connects to hang barrier from ceiling or existing overhead door track. KYODGMS includes built-in warning sirens and flashing lights; requires 2 9V lithium batteries, which are not included.