These jack stands are constructed completely of aluminum. Each part is hand fitted and jig welded. These jack stands weigh only 7-1/2 pounds each. They feature an anti-sink plate to keep the stand stable on dirt and to keep it from sinking into hot asphalt. The collapsed height is 14" and the extended height is 20-1/2". Available with a 4" wide or a 5" wide top support. These lightweight stands make working on your car more manageable.