Mega bird spike is a physical bird deterrent used to prevent large birds like seagulls, cormorants, turkey vultures, raptors and more from landing or roosting. The bird spikes are 7 in high and cover a 5 in wide ledge. The spikes bird come in 2 ft sections and are sold in boxes of 50 ft. Not recommended in areas where birds have been nesting. Wider ledges will require multiple rows.