Heavy-duty 1/4" thick rubber and individual vacuum lever for sure grip when it matters. Rugged impact-resistant ABS construction. For best results, use on smooth non-porous surface; both surface and rubber cup should be clean and free from dirt. Apply pressure to handle against surface while lifting levers; lubricating cup rim with small amount of rubber preservative or other liquid typically enhances rubber-to-surface seal and helps improve vacuum strength. Applying excessive lubrication may allow undesired cup movement on surface.
