The barrier at turn five now consists of old auto tires, standing up perpendicular to a reinforced guardrail.

These barriers consist of closely spaced poles, fixed below ground, carrying three high-tension thick wound cables.

In most areas, the barrier consists of an electronic fence accompanied by razor wire, trenches and guard towers.

In the San Diego area, the secondary barrier consists of concrete columns spaced a few inches apart.

However, the barriers consisted of three separate belts of wire requiring hours to cut.

The experimental barriers consist of a wall of plastic netting accompanied by an electric fence.

The barrier consisted of minuscule land mines and microphones that could be dropped from airplanes.

The barrier as a whole consists of various small waterfalls, rapids and basins.

In general, the barriers that separate species do not consist of just one mechanism.

The pneumatic barrier consists of perforated pipe and a compressed air source.